FORM 6-K SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Report of Foreign Issuer Pursuant to Rule 13a-16 or 15d-16 of the Securities Exchange Act of 1934 For the month of April, 2024 Commission File Number: 001-12518 Banco Santander, S.A. (Exact name of registrant as specified in its charter) Ciudad Grupo Santander 28660 Boadilla del Monte (Madrid) Spain (Address of principal executive office) Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F: Form 20-F ☒ Form 40-F ☐

BANCO SANTANDER, S.A. ________________________ TABLE OF CONTENTS Item 1. January - March 2024 Earnings presentation

Earnings Presentation Q1’24 30 April 2024

2 Important information Non-IFRS and alternative performance measures This presentation contains financial information prepared according to International Financial Reporting Standards (IFRS) and taken from our consolidated financial statements, as well as alternative performance measures (APMs) as defined in the Guidelines on Alternative Performance Measures issued by the European Securities and Markets Authority (ESMA) on 5 October 2015, and other non-IFRS measures. The APMs and non-IFRS measures were calculated with information from Grupo Santander; however, they are neither defined or detailed in the applicable financial reporting framework nor audited or reviewed by our auditors. We use these APMs and non-IFRS measures when planning, monitoring and evaluating our performance. We consider them to be useful metrics for our management and investors to compare operating performance between periods. APMs we use are presented unless otherwise specified on a constant FX basis, which is computed by adjusting comparative period reported data for the effects of foreign currency translation differences, which distort period-on-period comparisons. Nonetheless, the APMs and non-IFRS measures are supplemental information; their purpose is not to substitute IFRS measures. Furthermore, companies in our industry and others may calculate or use APMs and non-IFRS measures differently, thus making them less useful for comparison purposes. APMs using ESG labels have not been calculated in accordance with the Taxonomy Regulation or with the indicators for principal adverse impact in SFDR. For further details on APMs and Non-IFRS Measures, including their definition or a reconciliation between any applicable management indicators and the financial data presented in the consolidated financial statements prepared under IFRS, please see the 2023 Annual Report on Form 20-F filed with the U.S. Securities and Exchange Commission (the SEC) on 21 February 2024 (https://www.santander.com/content/dam/santander-com/en/documentos/informacion-sobre- resultados-semestrales-y-anuales-suministrada-a-la-sec/2024/sec-2023-annual-20-f-2023-en.pdf), as well as the section “Alternative performance measures” of Banco Santander, S.A. (Santander) Q1 2024 Financial Report, published on 30 April 2024 (https://www.santander.com/en/shareholders-and-investors/financial-and-economic-information#quarterly-results). Underlying measures, which are included in this document, are non-IFRS measures. The businesses included in each of our geographic segments and the accounting principles under which their results are presented here may differ from the businesses included and local applicable accounting principles of our public subsidiaries in such geographies. Accordingly, the results of operations and trends shown for our geographic segments may differ materially from those of such subsidiaries. Non-financial information This presentation contains, in addition to financial information, non-financial information (NFI), including environmental, social and governance-related metrics, statements, goals, commitments and opinions. NFI is not audited nor reviewed by an external auditor. NFI is prepared following various external and internal frameworks, reporting guidelines and measurement, collection and verification methods and practices, which are materially different from those applicable to financial information and are in many cases emerging and evolving. NFI is based on various materiality thresholds, estimates, assumptions, judgments and underlying data derived internally and from third parties. NFI is thus subject to significant measurement uncertainties, may not be comparable to NFI of other companies or over time or across periods and its inclusion is not meant to imply that the information is fit for any particular purpose or that it is material to us under mandatory reporting standards. NFI is for informational purposes only and without any liability being accepted in connection with it except where such liability cannot be limited under overriding provisions of applicable law. Forward-looking statements Santander hereby warns that this presentation contains “forward-looking statements” as per the meaning of the U.S. Private Securities Litigation Reform Act of 1995. Such statements can be understood through words and expressions like “expect”, “project”, “anticipate”, “should”, “intend”, “probability”, “risk”, “VaR”, “RoRAC”, “RoRWA”, “TNAV”, “target”, “goal”, “objective”, “estimate”, “future”, “commitment”, “commit”, “focus”, “pledge” and similar expressions. They include (but are not limited to) statements on future business development, shareholder remuneration policy and NFI. While these forward-looking statements represent our judgement and future expectations concerning our business developments and results may differ materially from those anticipated, expected, projected or assumed in forward-looking statements.

3 Important information In particular, forward looking statements are based on current expectations and future estimates about Santander’s and third-parties’ operations and businesses and address matters that are uncertain to varying degrees and may change, including, but not limited to (a) expectations, targets, objectives, strategies and goals relating to environmental, social, safety and governance performance, including expectations regarding future execution of Santander’s and third-parties’ (including governments and other public actors) energy and climate strategies, and the underlying assumptions and estimated impacts on Santander’s and third-parties’ businesses related thereto; (b) Santander’s and third-parties’ approach, plans and expectations in relation to carbon use and targeted reductions of emissions, which may be affected by conflicting interests such as energy security; (c) changes in operations or investments under existing or future environmental laws and regulations; (d) changes in rules and regulations, regulatory requirements and internal policies, including those related to climate-related initiatives ; (e) our own decisions and actions including those affecting or changing our practices, operations, priorities, strategies, policies or procedures; and (f) the uncertainty over the scope of actions that may be required by us, governments and others to achieve goals relating to climate, environmental and social matters, as well as the evolving nature of underlying science and industry and governmental standards and regulations. In addition, the important factors described in this presentation and other risk factors, uncertainties or contingencies detailed in our most recent Form 20-F and subsequent 6-Ks filed with, or furnished to, the SEC, as well as other unknown or unpredictable factors, could affect our future development and results and could lead to outcomes materially different from what our forward-looking statements anticipate, expect, project or assume. Forward-looking statements are therefore aspirational, should be regarded as indicative, preliminary and for illustrative purposes only, speak only as of the date of this presentation, are informed by the knowledge, information and views available on such date and are subject to change without notice. Santander is not required to update or revise any forward-looking statements, regardless of new information, future events or otherwise, except as required by applicable law. Santander does not accept any liability in connection with forward-looking statements except where such liability cannot be limited under overriding provisions of applicable law. Not a securities offer This presentation and the information it contains does not constitute an offer to sell nor the solicitation of an offer to buy any securities. Past performance does not indicate future outcomes Statements about historical performance or growth rates must not be construed as suggesting that future performance, share price or results (including earnings per share) will necessarily be the same or higher than in a previous period. Nothing in this presentation should be taken as a profit and loss forecast. Third Party Information In this presentation, Santander relies on and refers to certain information and statistics obtained from publicly-available information and third-party sources, which it believes to be reliable. Neither Santander nor its directors, officers and employees have independently verified the accuracy or completeness of any such publicly-available and third-party information, make any representation or warranty as to the quality, fitness for a particular purpose, non-infringement, accuracy or completeness of such information or undertake any obligation to update such information after the date of this presentation. In no event shall Santander be liable for any use by any party of, for any decision made or action taken by any party in reliance upon, or for inaccuracies or errors in, or omission from, such publicly-available and third-party information contained herein. Any sources of publicly-available information and third-party information referred or contained herein retain all rights with respect to such information and use of such information herein shall not be deemed to grant a license to any third party. Note: Quarterly series include adjustments relating to revenue sharing criteria between CIB and Retail & Commercial Banking to better reflect business dynamics of our new operating model with five global businesses as new primary segments; these adjustments do not affect results at the Group level, nor do they affect the full-year results of Retail & Commercial Banking and CIB. Quarterly series also include adjustments to some of the 2023 business volumes metrics in Retail & Commercial Banking, Digital Consumer Bank, CIB and Wealth Management & Insurance to better reflect our five global businesses’ perimeters according to our new operating model; these adjustments do not affect business volumes metrics at the Group level.

4 Index 1 Q1'24 Highlights Progress on our strategy Group review 2 Final remarks 3 Appendix 4

5 Strong first quarter performance with all our global businesses contributing to our 2024 targets Note: YoY changes. In constant euros: Attributable Profit +9%; Revenue +9%. P&L accounts are all presented in underlying basis. All references to variations in constant euros across the presentation include Argentina in current euros to mitigate distortions from a hyperinflationary economy. TNAVps + Cash DPS includes the €8.10 cent cash dividend paid in November 2023 and the €9.50 cent cash dividend approved in March (to be paid from 2 May), executed as part of the shareholder remuneration policy. Continued momentum in revenue growth driven by 5mn new customers YoY and good activity levels Strong operating performance and growth in profitability backed by first year of ONE Transformation FL CET1 TNAVps + DPS RoTE Q1’24 attributable profit Q1’24 revenue €2.9bn €15.4bn +10%+11% +55bps - +14% 42.6% -153bps Solid balance sheet and increasing shareholder remuneration supporting sustained value creation 14.9% 16.2% annualizing the temporary levy impact Efficiency 12.3%

6 Strong YoY profit increase, with double-digit growth in net operating income, supported by customer revenue and efficiency improvements Note: underlying P&L. (*) Including the temporary levy on revenue earned in Spain (-€335mn in Q1’24 and -€224mn in Q1’23). P&L Current Constant € million Q1'24 Q1'23 % % NII 11,983 10,185 18 16 Net fee income 3,240 3,043 6 5 Other income 157 707 -78 -78 Total revenue 15,380 13,935 10 9 Operating expenses -6,547 -6,145 7 5 Net operating income 8,833 7,790 13 11 LLPs -3,125 -2,873 9 7 Other results* -1,125 -822 37 34 Attributable profit 2,852 2,571 11 9 2024 has started with excellent business and commercial dynamics • Outstanding NII growth • Record net fee income • C/I and RoTE improvement

7 Strong start to the year, which puts us on track to deliver our 2024 targets, or even overdeliver some of them… (1) YoY change in constant euros, except Argentina in current euros. Revenue1 Efficiency CoR FL CET1 RoTE Q1’24 2024 targets 9% 42.6% <43% 1.20% c.1.2% 12.3% >12.0% 14.9% 16% Mid-single digit growth after Basel III implementation 16.2% annualizing the temporary levy impact

8 … backed by consistent execution of ONE Transformation… Reminder from Investor Day Efficiency 2022-2025 • Multi-Nationals: +5% YoY revenue growth • Wealth: collaboration fees with CIB and Corporates reached €988mn (+12% vs. Q1’23) • Consumer: expansion of OEM agreements • Product simplification: 2% fewer products in Q1’24 (-18% vs. Dec-22) • 58% products / services digitally available (+2pp vs. Dec-23) • In US, $10mn efficiencies in Q1’24 ($210mn since 2022) captured in Consumer and Commercial 200-250bps c. 42% 100-150bps 50-75bps FY’22 ONE Transformation Global & Network businesses Global Tech capabilities & others 2025 target Q1’24FY’22 Note: Q1’24 or latest available data. Efficiency execution 2022-Q1’24 42.6% 45.8% 45.8% • Global approach to technology: €50mn efficiencies in Q1’24 (€237mn since 2022) - Gravity (back-end) efficiencies - Process optimization - Global vendor agreements - IT&Ops shared-services -174bps -88bps -63bps

9 … and value added by our five global businesses, which are accelerating the achievement of our ID targets 52% 20% 13% 6% 9% Revenue (€bn) Contribution to Group’s revenue1 C/I RoTE2 Q1’24 2025 RoTE2 target c.17% >14% >20% c.60% >30% 15-17% Note: revenue YoY change in constant euros. (1) As % of total operating areas, excluding Corporate Centre. (2) Global businesses’ RoTEs are adjusted based on Group’s deployed capital. Data are presented annualizing the impact of the temporary levy. Without annualizing its impact: Retail 15.6% (+2.3pp); Consumer 11.2% (-0.5pp); CIB 19.2% (-2.5pp), Wealth 77.3% (+9.1pp), PagoNxt EBITDA 17.0% (not affected) and Group 14.9% (+0.55pp). Retail Consumer CIB Wealth Payments Group PagoNxt EBITDA margin 41.1% 17.6% -3.9pp +2.9pp 41.2% 11.9% -1.9pp -0.3pp 42.0% 19.7% +5.0pp -2.4pp 34.4% 80.4% -4.0pp +9.4pp 48.1% 17.0% +3.3pp +9.5pp 42.6% 16.2% -1.5pp +0.9pp 8.0 +13% 3.2 +4% 2.1 +5% 0.9 +17% 1.4 -0% 15.4 +9%

10 Retail: strong profit growth YoY with solid C/I driven by revenue and cost control New digital onboarding and products leading to an increase in digital customers and digital sales Customer experience # of products1 (k) # of non-commercial FTEs1 per mn total customers Active customers (mn) Execution of the strategy New model and automation reducing operational resources and driving increase in commercial focus in branches Operational leverage Global platform Scale of new platform (ODS-Gravity) reducing cost per technical transaction and driving efficiencies Key drivers Driving growth and efficiency on the back of our new model and proprietary technology Note: data and YoY changes in constant euros. RoTE annualizing the impact of the temporary levy. (1) Metrics cover all products and employees in the branch network in our 10 main countries. Loans Deposits C/I CoR RoTEProfit Operational leverage – Revenue vs. Costs (€ mn, excl. Argentina) €621bn -2% €642bn +2% 41.1% -3.9pp 1.03% +11bps 17.6% +2.9pp €1,503mn +22% Revenue Costs 74.6 76.0 Dec-22 Mar-24 10.1 8.2 Dec-22 Mar-24 +2% 657 630 Jun-23 Mar-24 -18% -4% €3bn Q1’24 financials

11 Consumer: strong net operating income growth with successful deposit gathering Providing global solutions integrated in our partners’ processes Expanding partnerships across regions Customer experience Simplifying and automating our processes Launched a new digital onboarding for pure digital players Openbank launch in the US and Mexico Expanding the functionality of our new leasing platform Operational leverage Global platform Transforming into a best-in-class, global business and operating model Loans Deposits C/I CoR RoTEProfit €208bn €119bn +4% +13% 41.2% -1.9pp 2.12% +32bps 11.9% -0.3pp Q1’24 financials €464mn -5% Key drivers Operating performance Non-auto Auto Retail deposits cost-to-serve (%) Total customers (mn) +2% 921 940 Q1'23 Q1'24 2,136 2,244 Q1'23 Q1'24 +5% 25.2 25.0 Dec-22 Mar-24 1.18 1.00 2022 Q1'24 -0.18pp Operating expenses / ANEAs (%) Note: data and YoY changes in constant euros. RoTE annualizing the impact of the temporary levy. ANEAs = Average net earning assets, including renting. CostsRevenue RevenueOperational leverage +4% -0.2%-0% Execution of the strategy

12 Enhanced centres of expertise, with new and strengthened industry and product teams Significant progress building new capabilities in the US Expansion on new value-added areas of growth Increased distribution capabilities, evolving our originate-to- share model towards a mainstream end-to-end platform Key drivers Playing to our strengths to better serve our corporate customers and institutions Loans Deposits C/I CoR RoTEProfit Fee growth (€ bn) % Total revenue / RWAs % customer related revenue €139bn €143bn -1% +1% 42.0% +5.0pp 0.14% -2bps 19.7% -2.4pp Customer experience Operational leverage Global platform €705mn -5% 80% 82 81 2022 Q1'24 Dec-22 +7% +1.2pp Dec-22 CIB: all-time high revenue. Profit down from a record Q1’23, impacted by investments Note: data and YoY changes in constant euros. RoTE annualizing the impact of the temporary levy. 0.6 0.7 Q1'23 Q1'24 5.9 7.1 2022 Q1'24 Revenue (€ mn) Global Transaction Banking (GTB) Global Markets Global Banking -3% +18% +12% 728 710 Q1'23 Q1'24 525 621 Q1'23 Q1'24 733 818 Q1'23 Q1'24 Q1’24 financialsExecution of the strategy

13 Wealth: double-digit growth across businesses with record commercial activity Named again Best Private Bank in LatAm (Euromoney) while growing our customer base by +13% YoY Boosted results by fostering collaboration with Retail and CIB, and by simplifying our product offer in SAM and Insurance Kicked off our global investments platform project to further digitalize our investment distribution capabilities Key drivers Accelerating our customers’ connectivity with our global product platforms Net new money (PB) Net sales (SAM) C/I Gross written premiums RoTEPAT + fees3 Revenue (including ceded fees, € mn) Santander Asset Management Insurance Private Banking Note: data and YoY changes in constant euros. RoTE annualizing the impact of the temporary levy. (1) Includes off-balance sheet assets and deposits. (2) Considering annualized net new money as % of total CAL and annualized net sales as % of SAM AuMs. (3) Includes all fees generated by Santander Asset Management and Insurance, even those ceded to the commercial network, which are reflected in Retail & Commercial Banking’s P&L. Collaboration fees (€ bn) Revenue growth including ceded fees3 (€ bn) Assets under management1 (€ bn) 7% €3.8bn 7% €3.0bn -4% 80.4% +9.4pp 34.4% -4.0pp 297 341 Q1'23 Q1'24 531 625 Q1'23 Q1'24 526 574 Q1'23 Q1'24 +15%+18% +9% Customer experience Operational leverage Global platform €5.5bn €838mn +16% 409 482 Dec-22 Mar-24 0.88 0.99 Q1'23 Q1'24 1.4 1.5 Q1'23 Q1'24 +18% +12% +14% of volumes2 of volumes2 Q1’24 financialsExecution of the strategy

14 +5% New wallet agreements to offer customers alternative payment options Continued strengthening PagoNxt’s customer value proposition Capex optimization and operational efficiencies driving down cost per transaction Global Cards platform (Plard) launched in Brazil Key drivers Seizing a growing opportunity by capturing scale through global platforms Active customers Ebury Revenue (€ mn) PagoNxt Cards Note: data and YoY changes in constant euros. Transactions include merchant payments, cards and electronic A2A payments. (1) Excluding a one-time positive fee recorded in the first quarter of 2023 from commercial agreements in Brazil. Cost per transaction (€ cents, PagoNxt) % open market revenue (PagoNxt) # transactions (bn per month) 250 283 Q1'23 Q1'24 1,105 1,070 Q1'23 Q1'24 -3%+13% Customer experience Operational leverage Global platform % growth exc. Q1’23 one-off1 2.6 3.2 2022 Q1'24 4.1 3.6 2022 Q1'24 13.6 21.9 2022 Q1'24 +21% -13% +8.3pp TPV Getnet €54bn +14% Turnover Cards C/I Payments +3.3pp 48.1% Profit Payments €137mn +22% EBITDA margin PagoNxt Payments: sound credit quality led to double-digit profit growth 17.0% +9.5pp €78bn +6% 22k +20% Q1’24 financialsExecution of the strategy

15 Note: our shareholder remuneration policy is c.50% payout split in approximately equal parts (cash and share buybacks). Implementation of shareholder remuneration policy is subject to future corporate and regulatory decisions and approvals. (1) TNAVps + Cash DPS includes the €8.10 cent cash dividend paid in November 2023 and the €9.50 cent cash dividend approved in March (to be paid from 2 May), executed as part of the shareholder remuneration policy. +14% Outstanding profitability and value creation with 14% YoY growth in TNAVps + Cash DPS TNAVps + Cash DPS € per share Cash DPS: €17.6 cents 4.41 4.86 5.04 Mar-23 Mar-24 1 EPSRoTE 14.4 14.9 15.3 16.2 Q1'23 Q1'24 % € cents Since 2021 and including full execution of second share buyback against 2023 results currently in place, Santander will have repurchased c.11% of its outstanding shares 15.0 17.0 Q1'23 Q1'24 +14%+93bps Annualizing the impact of the temporary levy

16 Index 1 Q1'24 Highlights Progress of our strategy Group review 2 Final remarks 3 Appendix 4

17 Strong profit increase YoY, with double-digit growth in net operating income, supported by customer revenue and efficiency improvements -3% 2,571 2,670 2,902 2,933 2,852 Q1'23 Q2 Q3 Q4 Q1'24 € mn Attributable profit Attributable profit (Constant € mn) Note: underlying P&L. (*) Including the temporary levy on revenue earned in Spain (-€335mn in Q1’24 and -€224mn in Q1’23). QoQ 2,620 2,675 2,907 2,930 2,852 +11% +9% excluding temporary levy +14% excluding temporary levy P&L Current Constant € million Q1'24 Q1'23 % % NII 11,983 10,185 18 16 Net fee income 3,240 3,043 6 5 Other income 157 707 -78 -78 Total revenue 15,380 13,935 10 9 Operating expenses -6,547 -6,145 7 5 Net operating income 8,833 7,790 13 11 LLPs -3,125 -2,873 9 7 Other results* -1,125 -822 37 34 Attributable profit 2,852 2,571 11 9

18 14,157 14,355 14,839 14,546 15,380 Q1'23 Q2 Q3 Q4 Q1'24 15,380 -1 -86 14,157 +957 +128 +98 +127 Q1'23 Retail Consumer CIB Wealth Payments CC Q1'24 High-single digit revenue growth backed by customer activity across businesses NII + Fees Other income YoY growth Total revenue • >95% of total revenue is customer related which drove the vast majority of total revenue growth • Strong revenue increase YoY reflecting the benefits of our diversification, with all businesses and regions contributing • Retail up double-digit, in a context of solid commercial activity and good margin management across regions • Consumer grew backed by DCB Europe (higher volumes and active repricing) and Brazil (higher activity and lower interest rates) • CIB increased to record levels, supported by Global Markets and Global Banking; solid behaviour in the US (+35%) and Mexico (+45%) • Wealth rose strongly backed by good commercial activity across businesses and good margin management in Private Banking • Payments up 7% excluding a one-time positive fee in Cards in Q1’23 from commercial agreements. Of note, PagoNxt +13% Total revenue Group Detail by business +9% +9% +13% +4% +5% +17% -0% Note: data and YoY % changes in constant euros.

19 2.63% 2.73% 2.82% 2.76% 2.97% Net interest income and NIM 10,367 10,793 11,220 11,123 11,983 Q1'23 Q2 Q3 Q4 Q1'24 NII and NIM up YoY, supported by volumes and margin improvement Net interest income Margins NIM Quarterly NII NIM Note: NIM = NII / Average earning assets. Data and YoY % changes in constant euros. • >80% of Group’s NII is from Retail and Consumer businesses • Growth YoY across all business and regions − Retail in Europe and North America supported by active liability management in a context of higher interest rates − Retail in South America and Consumer benefitted from negative sensitivity to interest rates, especially Brazil • NII up 8% QoQ with all businesses growing − Growth accelerating in businesses with negative sensitivity: Retail South America (+35%), Consumer Brazil (+11%) − Good liability management and lower volumes kept NII fairly stable in businesses with positive sensitivity (Retail in Europe and North America) • NIM improved YoY and QoQ, driven by asset repricing and cost of deposits under control • NIM trend reflecting the strength of our European franchise, mostly funded with stable retail deposits, and good momentum in South America +16% 2.97% -0.58 -0.12 2.63% +0.81 +0.23 Q1'23 Asset yields Asset volumes Liability costs Liability volumes Q1'24

20 3,092 3,063 3,105 2,832 3,240 Q1'23 Q2 Q3 Q4 Q1'24 Net fee income growth, demonstrating the value added from our business diversification Note: data and YoY % changes in constant euros. YoY growth 3,240 -114 3,092 +99 +65 +41 +54 +2 Q1'23 Retail Consumer CIB Wealth Payments CC Q1'24 Net fee income +5% +5% Retail CIB Wealth Consumer Payments • Good commercial dynamics in most countries, with all regions growing • Fee income boosted by higher transactionality mainly in Brazil, Mexico and Poland • Outstanding performance driven by higher activity in DCB Europe and Brazil • Expanding existing partnerships across regions • Solid growth supported by all CIB businesses, of note, Global Banking (+20%) • Robust activity levels in Global Banking, both Global Debt Financing and Corporate Finance, and Global Markets • Strong growth across the three businesses • Increase backed by more recurrent activity in PB, higher volumes in SAM and protection business performance in Insurance • Payments affected by a one-time positive fee in Cards in Q1’23 from commercial agreements • Strong total payments volume growth (+14% YoY) and transactions (+13% YoY) backed by Europe and Mexico +9% +22% +7% +17% -14%

21 -0% -4% +15% +1% +4% -11% ( in real terms1)+1.1% 6,547 -2 -7 6,222 +132 +140 +14 +49 Q1'23 Retail Consumer CIB Wealth Payments CC Q1'24 ONE Transformation is driving structural efficiency gains and positive jaws Note: data and YoY % changes in constant euros. (1) Costs in real terms exclude the impact from weighted average inflation. Efficiency and costs Costs YoY growth in real terms1 Efficiency Quarterly Costs • Costs fairly stable for the third quarter in a row at around €6.5bn, and +1% YoY in real terms • Retail: costs well under control, despite impacts from salary agreements reviews in some countries and transformation efforts • Consumer: cost reduction despite investments and business growth • CIB growth impacted by investments in new products and capabilities in line with our strategy • Wealth growing slightly, well below revenue, due to higher commercial activity and investments to reinforce our PB teams • Payments growth due to both Cards and PagoNxt, which are still in an investment phase • Corporate Centre down driven by ongoing simplification measures 6,222 6,354 6,463 6,465 6,547 Q1'23 Q2 Q3 Q4 Q1'24 44.1% 44.3% 43.6% 44.4% 42.6% +5% Efficiency • Transformation towards simpler and more integrated models continues to drive efficiency gains • Efficiency improved to 42.6% (-1.5 pp YoY; Retail -3.9 pp), within our 2024 target of <43% • Transformation investments (technology) in Q1’24 totalled €0.5bn (€2.9bn since 2022)

22 2,922 2,919 3,254 3,416 3,125 Q1'23 Q2 Q3 Q4 Q1'24 Credit quality remains robust CoR LLPs Other credit quality metrics Note: CoR - provisions to cover losses due to impairment of loans in the last 12 months / average customer loans and advances of the last 12 months. Data in constant euros. 1.05% 1.08% 1.13% 1.18% 1.20% Mar-23 Dec-23 Mar-24 NPL ratio 3.05% 3.14% 3.10% Coverage ratio 68% 66% 66% Stage 1 €1,005bn €1,000bn €1,007bn Stage 2 €72bn €80bn €83bn Stage 3 €34bn €36bn €36bn Credit quality Detail by business • In Retail, which represents 49% of Group’s LLPs, CoR remained stable QoQ at 1.03% − Spain improving CoR, with stable NPL YoY − UK CoR at very low levels − Brazil NPL improving both QoQ and YoY, and Mexico normalizing in line with expectations affected by mix change • In Consumer, which represents 36% of Group’s LLPs, CoR normalized YoY to 2.12% (mainly Consumer US business), in line with expectations, while remained fairly stable QoQ • Credit quality remains robust, backed by overall good economic performance and record low unemployment in most countries • NPL ratio stood at 3.10% (3.14% Dec-23) with NPL coverage and stages stable LLPs and credit quality

23 Front book pricing RoRWA of new book 2.8% Strong capital generation, profitable front-book growth >15% RoTE and significant RWA mobilization % (1) Shareholder remuneration charged against profit earned in Q1 2024 (split between cash dividends and share buybacks) in line with our 50% payout target. Execution of the shareholder remuneration policy is subject to future corporate and regulatory decisions and approvals. 1 12.3 -0.22 -0.24 12.3 +0.32 +0.14 Dec-23 Organic generation Shareholder remuneration Regulatory & models Markets & others Mar-24 CET1 performance and capital productivity FL CET1 % RWAs with RoRWA > CoE Asset rotation and risk transfer activities RWAs mobilized vs. credit RWAs Maximize capital productivity 83% 12% Mar-24 or estimates

24 Index 1 Q1'24 Highlights Progress of our strategy Group review 2 Final remarks 3 Appendix 4

25 RoTE1 Profitability FL CET1 Strength RWAs with RoRWA > CoE Disciplined capital allocation Payout 50% Shareholder remuneration Note: execution of the shareholder remuneration policy is subject to future corporate and regulatory decisions and approvals. (1) RoTE is presented annualizing the temporary levy. >12% c.85% 15-17% Q1’24 vs. 2025 ID targets Making progress towards our ID target in our new phase of value creation for our shareholders Cash dividend + SBB 50% annually 83%TNAVps + DPS Double-digit growth average through-the-cycle +14% 16.2% 12.3%

26 12.3% €15.4bn 2024 has begun with excellent business and commercial dynamics Note: our shareholder remuneration policy is c.50% payout split in approximately equal parts (cash and share buybacks). Implementation of shareholder remuneration policy is subject to future corporate and regulatory decisions and approvals. TNAVps + Cash DPS includes the €8.10 cent cash dividend paid in November 2023 and the €9.50 cent cash dividend approved in March (to be paid from 2 May), executed as part of the shareholder remuneration policy. Structural efficiency gains and profitable growth driven by strategy execution Profitability, capital and credit quality in line with targets Organic capital generation to mitigate accelerated Basel III implementation TNAVps + Cash DPS growing 14% YoY in our new phase of value creation for our shareholders Outstanding customer revenue performance backed by all global businesses ONE Transformation and value-added by our global businesses accelerating the achievement of our ID targets Efficiency 42.6% TNAVps + DPS +14% FL CET1 Profit €2.9bn Revenue

27 Index 1 Q1'24 Highlights Progress of our strategy Group review 2 Final remarks 3 Appendix 4

28 Appendix Investor Day Targets summary Detail by global business, region and country Reconciliation of underlying results to statutory results Glossary The other information in the Appendix regularly provided each quarter can be found in the document entitled "Supplementary Information", published together with this presentation on the Group's corporate website

29 (1) Target payout defined as c.50% of Group reported profit (excluding non-cash, non-capital ratios impact items), distributed in approximately 50% in cash dividend and 50% in share buybacks. Execution of the shareholder remuneration policy is subject to future corporate and regulatory decisions and approvals. (2) Those customers who meet transactionality threshold in the past 90 days. (3) Total transactions annual growth include merchant payments, cards and electronic A2A payments. Target c.+8% CAGR 2022-25. (4) Information is audited on a limited assurance basis. Green finance raised & facilitated (€bn): since 2019 (not EU taxonomy aligned). Financial inclusion (# people, mn): since 2023. Definitions in the Glossary section in this document. Equal pay gap is annually calculated. ONE Transformation driving double-digit growth in value creation TNAVps+DPS (Growth YoY) Double-digit growth average through-the-cycle +6% +15% RoTE (%) Payout (Cash + SBB)1 (%) EPS Growth (%) Total customers (mn) Active customers (mn)2 Simplification & automation Efficiency ratio (%) Customer activity Transactions volume per active customer (month, % growth)3 FL CET1 (%) RWA with RoRWA > CoE (%) Green financed raised & facilitated (€bn) Socially responsible Investments (AuM) (€bn) Financial inclusion (# People, mn) Women in leadership positions (%) Equal pay gap (%) Profitability Customer centric Capital ESG4 2022 2023 Q1'24 2025 targets 13.4 15.1 14.9 15-17 40 50 50 50 23 21.5 13.7 Double-digit 160 165 166 c.200 99 100 100 c.125 45.8 44.1 42.6 c.42 - 10 11 c.+8 12.0 12.3 12.3 >12 80 84 83 c.85 94.5 114.6 118.5 120 53 67.7 72.8 100 - 1.8 2.3 5 c.29 31.4 31.4 35 c.1 c.0 - c.0 +14%

30 Appendix Investor Day Targets summary Detail by global business, region and country Reconciliation of underlying results to statutory results Glossary The other information in the Appendix regularly provided each quarter can be found in the document entitled "Supplementary Information", published together with this presentation on the Group's corporate website

31 Detail by global business

32 Retail & Commercial Banking Highlights Loans Deposits Mutual Funds Efficiency CoR RoTE Key data Note: RoTE annualizing the impact of the temporary levy. Underlying P&L €621bn -2% €642bn +2% €89bn +13% 41.1% -3.9pp 1.03% +11bps 17.6% +2.9pp •Convergence towards a common business and operating model, our transformation and disciplined capital allocation are reflected in significant total customer growth, and improvements in efficiency (-4pp to 41.1%) and profitability (RoTE +3pp to 17.6%) • Loans down YoY, affected by prepayments in Europe (especially mortgages), partially offset by growth in South America and Mexico. Deposits up, mainly time deposits across countries and segments • Strong profit growth YoY (+22%), despite the impact from the temporary levy, with solid revenue performance and lower LLPs: - NII rose with widespread growth across our footprint, especially Spain, Portugal, Brazil, Argentina and, to a lesser extent, Mexico and Poland - Solid fee performance, mainly due to higher activity in funds and insurance - Provisions improved mainly due to the good credit quality performance in Europe. CoR under control at comfortable levels (1.03%) • In the quarter, good net operating income performance and lower LLPs. This performance was not reflected in profit due to the temporary levy and a higher tax burden Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 7,145 10.7 17.3 20.5 Net fee income 1,193 17.5 9.1 11.0 Total revenue 8,048 8.8 13.5 16.3 Operating expenses -3,304 6.7 4.1 6.2 Net operating income 4,744 10.3 21.1 24.5 LLPs -1,523 -11.8 -1.6 0.7 Attributable profit 1,503 -1.9 21.6 25.7 (*) € mn and % change in constant euros. (1) % change in current euros.

33 Digital Consumer Bank Highlights New lending Loans Deposits Efficiency CoR RoTE Key data Underlying P&L • We continue expanding our leadership in consumer finance across our footprint, while we focus on converging towards a more digital global operating model, using common platforms and with a global approach to our partnerships • Loans up 4% YoY, driven by strong activity in Europe (+6%) and Brazil (+8%) • Deposits rose 13%, mainly in Europe, reflecting our strategy to grow customer deposits to lower funding costs • Net operating income increased 7%, supported by positive revenue performance (+4%) and good cost control (-4% in real terms) • Profit down YoY, impacted by the temporary levy and higher provisions and cost of risk normalization, in line with expectations, and still below historical average levels • In the quarter, profit up 1% supported by growth of net interest income and fees, and good cost management, especially in the US, which more than offset the impact from the temporary levy in Q1 €21.6bn +7% €208bn +4% €119bn +13% 41.2% -1.9pp 2.12% +32bps 11.9% -0.3pp Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 2,710 4.7 6.6 6.4 Net fee income 354 7.4 22.4 23.0 Total revenue 3,185 1.2 4.2 4.0 Operating expenses -1,311 -4.1 -0.2 -0.5 Net operating income 1,874 5.3 7.5 7.4 LLPs -1,137 1.5 24.5 24.1 Attributable profit 464 1.5 -4.8 -5.0 (*) € mn and % change in constant euros. (1) % change in current euros. Note: RoTE annualizing the impact of the temporary levy.

34Note: Global Banking = GDF & CF. RoTE annualizing the impact of the temporary levy. Corporate & Investment Banking Highlights Key data Underlying P&L • We continue making our centres of expertise more sophisticated, deepening client relationships with a particular focus on the US build-out to complement our capabilities, and actively managing capital • Strong activity year-on-year, supported by an excellent quarter in Global Banking and Global Markets, slightly offset by Global Transaction Banking, due to Cash Management - Global Transaction Banking: another good quarter for Trade and Export Finance, however there was lower activity in Cash Management, impacted by interest rate cuts in LatAm - Global Banking grew both in Global Debt Finance, where we are gaining market share, and Corporate Finance, benefitting from positive market momentum, though still below historical averages - Good activity levels in Global Markets as European customers are normally more active in Q1 • Record quarterly revenue, up 5% vs. Q1’23. Profit impacted by our investments in transformation, products and new capabilities, in line with our strategy Loans Deposits Efficiency CoR RoTE 42.0% +5.0pp 0.14% -2bps 19.7% -2.4pp €139bn -1% €143bn +1% Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 1,062 2.4 25.3 25.8 Net fee income 654 39.2 6.8 7.9 Total revenue 2,112 24.4 4.8 5.4 Operating expenses -888 -11.9 18.8 19.7 Net operating income 1,225 77.2 -3.4 -3.0 LLPs -40 -80.5 — — Attributable profit 705 139.8 -5.1 -5.0 (*) € mn and % change in constant euros. (1) % change in current euros.

35 €482bn +14% €5.5bn 7% €3.8bn 7% €3.0bn -4% 34.4% -4.0pp 80.4% +9.4pp Gross written premiums Efficiency RoTE AuMs Net new money (PB) Net sales (SAM) Wealth Management & Insurance Highlights Key data Note: RoTE annualizing the impact of the temporary levy. (2) Considering annualized net new money over total CAL and net sales over SAM AuMs. (3) Including fees generated by asset management and insurance ceded to the commercial network. Underlying P&L • We continue building the best Wealth and Insurance manager in Europe and the Americas, supported by our leading global PB platform and best- in-class funds and insurance product factories • Euromoney named us the Best International Private Bank in Latin America for the second year in a row, and the Best International Private Bank in 8 of our countries • All-time high assets under management, up 14% YoY, as a result of record commercial activity in PB and SAM. In Insurance, GWPs dropped YoY after an extraordinary Q1’23 and impacted by a lower savings activity • 25% profit growth YoY, supported by strong revenue growth, both from NII (PB activity and good margin management) and fees in PB and SAM • Total fees3, including those ceded to the commercial network, increased 13% YoY, contributing 31% of the Group's total fees, with good performance across all three businesses • Wealth’s total contribution to the Group’s profit increased 16% YoY, in a capital-light business, reflected in a RoTE exceeding 80% of volumes2 of volumes2 Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 423 12.2 25.6 26.5 Net fee income 364 14.2 17.4 18.1 Total revenue 892 13.7 16.6 17.6 Operating expenses -306 -8.6 4.7 5.3 Net operating income 585 30.3 24.0 25.3 LLPs -4 — — — Attributable profit 400 11.6 24.9 26.5 Contribution to profit 838 7.3 16.4 18.3 (*) € mn and % change in constant euros. (1) % change in current euros.

36 Payments Note: in PagoNxt a negative growth rate indicates a lower loss. Number of cards managed by Cards equals to 99 million, because it excludes those managed by Digital Consumer Bank including Openbank (3 million cards). (2) Excluding a one-time positive fee recorded in the first quarter of 2023 from commercial agreements in Brazil. 7.5% 17.0% Q1'23 Q1'24 • Getnet: TPV increased 14% YoY and the number of transactions rose 13% YoY • Ebury: 22k active customers (+20% YoY) • Payments Hub already one of the largest A2A payments processors in Europe • Revenue increased 13% YoY due to an overall increase in business activity and volumes across countries, supporting EBITDA margin improvement to 17.0% PagoNxt underlying P&L Getnet Getnet Total Payments Volume (TPV) Number of transactions EBITDA margin Cards • Group total number of cards rose to 102 million, continuing the positive trends in previous quarters • Solid growth in customer activity (€78bn turnover, +6% YoY) • Revenue up 5% excluding Q1’23 positive one-off2 • High profitability with RoTE at 35.5% Cards Average balanceTurnover Underlying P&L €54bn +14% +9.5pp €78bn +6%+13% €22bn +6% Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 31 -18.7 216.6 230.9 Net fee income 224 -10.9 -0.1 2.5 Total revenue 283 -11.3 13.4 16.3 Operating expenses -304 14.2 8.4 9.7 Net operating income -21 — -32.0 -37.5 LLPs -4 207.6 -39.2 -39.0 Attributable profit -39 — -26.3 -28.7 (*) € mn and % change in constant euros. (1) % change in current euros. Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 644 18.3 9.0 12.5 Net fee income 452 -0.6 -20.0 -17.9 Total revenue 1,070 8.2 -3.1 -0.2 Operating expenses -346 22.1 7.8 11.0 Net operating income 724 2.6 -7.6 -4.8 LLPs -414 13.4 -14.1 -10.9 Attributable profit 177 -1.2 6.8 9.1 (*) € mn and % change in constant euros. (1) % change in current euros.

37 Corporate Centre • NII improved driven by higher liquidity buffer remuneration • Lower gains on financial transactions due to higher negative FX hedging impacts • Cost improved driven by ongoing simplification measures • Other results and provisions improved slightly YoY Highlights Income statement Underlying P&L* Q1'24 Q1'23 NII -31 -52 Gains / losses on financial transactions -162 -54 Operating expenses -87 -95 LLPs and other provisions -42 -41 Tax and minority interests -18 -19 Attributable profit -357 -279 (*) € mn.

38 Detail by region and country

39 Highlights Note: Q1’24 data and YoY changes (loans, deposits and mutual funds in constant euros). RoTE annualizing the impact of the temporary levy, 15.7% without annualizing it. Key data and P&L Loans Deposits Mutual Funds Efficiency CoR RoTE • We remain focused on growing our business while transforming our operating model to increase efficiency and boost customer experience • Customers up (+666k YoY) in all countries, mainly driven by consistent growth in Spain • New business lending volumes are recovering, however loans declined year-on-year, still affected by prepayments in a context of higher interest rates. Customer deposits rose, with strong increase in time deposits • Strong profit YoY supported by double-digit NII growth, especially in Retail, on the back of higher average interest rates and strict control of funding costs. Efficiency gains and active risk management • Profit up 17% QoQ, despite the temporary levy, with good performance across the main P&L lines except NII (lower volumes and higher costs of deposits in the UK) Europe Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 4,123 -0.7 11.8 14.6 Net fee income 1,202 11.8 1.6 2.9 Total revenue 5,809 10.8 10.1 12.3 Operating expenses -2,305 -2.8 4.5 6.4 Net operating income 3,504 22.0 14.1 16.7 LLPs -484 -17.5 -26.3 -24.6 Attributable profit 1,541 17.5 26.8 29.6 (*) € mn and % change in constant euros. (1) % change in current euros. €553bn -4% €614bn +1% €111bn +17% 39.7% -2.2pp 0.41% -1bps 18.0% +3.6pp

40 Spain UK España and UK Loans Deposits Mutual FundsLoans Deposits Mutual Funds Efficiency CoR RoTEEfficiency CoR RoTE • Sustained strong growth in customers. Drop in loans (mortgage prepayments, ICO maturities and CIB). Migration to time deposits trend continues, while mutual funds demand increases (12% YoY) • Profit +65% driven by higher NII, driven by margin management in a context of higher interest rates, especially in Retail, and robust credit quality performance • Profit up QoQ supported by the main lines, despite the negative impact of the temporary levy in Q1’24 • Loan volumes drop in a context of higher rates in line with our deleveraging strategy. Strong migration from demand to time deposits • Profit -25% YoY affected by the cost of deposits, lower mortgage volumes and cost increases • Profit flat QoQ as revenue (higher liability costs) and cost performance (personnel costs) were offset by lower LLPs €237bn -5% €228bn +2% €7bn +1% 58.4% +9.1pp 0.08% -4bps 10.4% -3.1pp Underlying P&L* Q1'24 % Q4'23 % Q1'23 NII 1,816 4.5 24.3 Net fee income 746 14.4 -0.8 Total revenue 3,016 28.8 18.4 Operating expenses -1,032 -6.2 1.8 Net operating income 1,984 59.9 29.4 LLPs -331 -3.3 -20.2 Attributable profit 772 49.5 65.5 (*) € mn and % change. Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 1,185 -4.4 -10.4 -7.6 Net fee income 79 4.6 -7.8 -4.9 Total revenue 1,257 -3.0 -10.9 -8.1 Operating expenses -734 3.9 5.6 8.9 Net operating income 523 -11.1 -27.0 -24.7 LLPs -17 -4.5 -71.7 -70.8 Attributable profit 305 0.1 -25.2 -22.8 (*) € mn and % change in constant euros. (1) % change in current euros. Note: Q1’24 data and YoY changes (loans, deposits and mutual funds in constant euros). Spain RoTE annualizing the impact of the temporary levy, 18.0% without annualizing it. €228bn -5% €299bn -1% €83bn +12% 34.2% -5.6pp 0.59% -4bps 23.3% +8.6pp

41 Portugal and Polonia Portugal PolandPoland Loans Deposits Mutual Funds Loans Deposits Mutual Funds Efficiency CoR RoTE Efficiency CoR RoTE • Loans: moderate decline as new business recovered, offsetting last year’s deleverage. Cost of deposits under control, affecting deposit volumes • Profit +69% YoY with strong NII, driven by interest rate increases and controlled funding costs, and net fee income. Solid credit quality with CoR at very low levels • Profit up QoQ due to fees, lower costs and strong LLPs performance • Loans rose mainly driven by Retail (lifetime record mortgage and personal loans sales) and CIB. Significant growth in deposits, especially time deposits • Profit up 18% YoY supported by good revenue performance (higher yields and volumes, with low cost of deposits), positive fees and underlying LLPs, which offset higher costs • Profit up QoQ, driven by favourable fees and lower CHF impacts €38bn -3% €37bn -2% €4bn +15% 22.9% -9.7pp 0.19% +13bps 31.1% +10.2pp €36bn +7% €45bn +6% €6bn +53% 27.5% +0.4pp 1.95% +24bps 20.1% +0.6pp Underlying P&L* Q1'24 % Q4'23 % Q1'23 NII 431 -4.5 65.1 Net fee income 127 14.3 2.6 Total revenue 584 0.0 44.1 Operating expenses -134 -4.9 1.2 Net operating income 450 1.6 64.9 LLPs -7 -60.9 -46.8 Attributable profit 303 3.7 68.6 (*) € mn and % change. Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 686 0.0 7.8 17.1 Net fee income 176 12.8 11.5 21.2 Total revenue 834 -2.5 5.2 14.4 Operating expenses -229 -6.8 6.7 16.0 Net operating income 605 -0.7 4.7 13.8 LLPs -130 -36.2 -20.8 -13.9 Attributable profit 213 45.6 17.7 28.0 (*) € mn and % change in constant euros. (1) % change in current euros. Note: Q1’24 data and YoY changes (loans, deposits and mutual funds in constant euros).

42 • We are focused on strengthening our leadership in auto and non-auto through strategic alliances and better service through new operational leasing and non-auto BNPL platforms • Loans rose 6% YoY, mainly driven by Auto (+7%). Customer deposits increased 21%, in line with our strategy to decrease our funding costs and reduce margin volatility across the interest rate cycle • Revenue up 5% YoY, mainly driven by NII, as we actively repriced loans and grew customer deposits. Strong increase in fees, driven by insurance in France and Germany • Profit down QoQ affected by seasonality, lower gains on financial transactions (down from high levels in 2023), and higher LLPs following portfolio sales in Q4’23 Note: Q1’24 data and YoY changes (new lending, loans and customer funds in constant euros). RoTE annualizing the impact of the temporary levy, 8.9% without annualizing it. Digital Consumer Bank Europe New lending Loans Customer Funds Highlights Key data and P&L Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 1,095 0.6 6.1 6.4 Net fee income 220 14.5 14.8 15.1 Total revenue 1,410 -2.0 4.7 5.0 Operating expenses -665 1.6 0.7 0.8 Net operating income 745 -5.1 8.6 9.0 LLPs -276 80.4 42.7 42.8 Attributable profit 229 -39.4 -6.3 -6.2 (*) € mn and % change in constant euros. (1) % change in current euros. Efficiency CoR RoTE €13bn -1% €135bn +6% €77bn +21% 47.1% -1.9pp 0.67% +19bps 9.9% -0.6pp

43 • Focus on transformation, leveraging the strengths of our businesses in the US and Mexico and enhancing our regional operating model in T&O • Solid loan growth, particularly in Mexico. Deposits are also increasing, mainly driven by Retail in Mexico and Consumer in the US • Revenue up 8% YoY driven by NII in Mexico (higher volumes) and strong performance of our CIB business across the region, particularly in the US • Costs grew, impacted by inflation and investments in transformation, CIB build out in the US and digitalization, partially offset by the efficiencies captured in Retail and Consumer in the US • Profit decreased slightly YoY as the strong revenue performance was offset by higher costs and LLPs, which were affected by expected normalization • Strong profit growth QoQ driven by revenue in CIB and Wealth in the US, better sequential LLPs (seasonality in Auto) and cost improvements, mainly in Mexico Note: Q1’24 data and YoY changes (loans, deposits and mutual funds in constant euros). North America Loans Deposits Mutual Funds Efficiency CoR RoTE Highlights Key data and P&L €167bn +3% €144bn +1% €32bn +5% 47.7% -0.1pp 2.15% +52bps 11.3% +0.8pp Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 2,611 -1.2 3.8 6.7 Net fee income 638 13.5 16.8 22.4 Total revenue 3,485 2.8 7.9 10.9 Operating expenses -1,661 -6.1 8.2 10.8 Net operating income 1,824 12.5 7.5 11.1 LLPs -985 -12.6 19.8 21.8 Attributable profit 644 39.4 -1.6 2.7 (*) € mn and % change in constant euros. (1) % change in current euros.

44 • Successful customer acquisition campaigns driving up loan volumes (Consumer and corporate loans) and time deposits • Profit up 6% YoY supported by double-digit revenue growth and improved efficiency. CoR rose in line with expectations • Profit growing QoQ, supported by cost improvements Note: Q1’24 data and YoY changes (loans, deposits and mutual funds in constant euros). (2) Adjusted RoTE: adjusted based on Group’s deployed capital calculated as contribution of RWAs at 12%. Using tangible equity, RoTE is 8.0%. Mexico Loans Deposits Mutual Funds Loans Deposits Mutual Funds Efficiency CoR RoTE2 Efficiency CoR RoTE US €115bn +1% €94bn -1% €13bn -12% 50.3% +0.4pp 1.98% +46bps 10.8% -0.8pp €51bn +8% €49bn +7% €19bn +21% 41.4% -0.2pp 2.63% +65bps 18.8% +0.8pp Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 1,396 -1.3 -3.6 -4.7 Net fee income 267 44.0 42.4 40.7 Total revenue 1,869 6.7 3.5 2.3 Operating expenses -940 -1.7 4.2 3.0 Net operating income 929 16.9 2.7 1.5 LLPs -615 -24.8 9.7 8.4 Attributable profit 279 328.4 -5.7 -6.8 (*) € mn and % change in constant euros. (1) % change in current euros. Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 1,214 -0.9 13.8 23.6 Net fee income 359 -1.2 3.5 12.3 Total revenue 1,608 -0.8 13.9 23.6 Operating expenses -665 -12.7 13.4 23.1 Net operating income 943 9.9 14.3 24.1 LLPs -370 19.7 42.4 54.6 Attributable profit 411 1.2 5.6 14.6 (*) € mn and % change in constant euros. (1) % change in current euros. • Lending slightly up, mainly driven by CIB activity. Deposits declined slightly with time growing at the expense of lower demand deposits • Good revenue performance YoY. However, profit down due to investments to improve our CIB franchise and LLP normalization • Strong profit growth QoQ, with outstanding fee performance and lower costs, and provisions down (seasonality in Q4)

45 South America Note: Q1’24 data and YoY changes (loans, deposits and mutual funds in constant euros). Loans Deposits Mutual Funds Efficiency CoR RoTE Highlights Key data and P&L €161bn +5% €133bn +6% €71bn +14% 37.4% -1.7pp 3.44% +5bps 14.8% -0.4pp • We are focused on being the primary bank for our 75 million customers, on becoming the most profitable in each of our countries and on enhancing service quality • Loans grew both QoQ and YoY, mainly in Brazil (Retail and Consumer) and Chile, with time deposits and mutual funds increasing also QoQ and YoY • Profit increased YoY, as strong NII growth across countries was mostly offset by higher costs (inflation and salary agreements) and higher provisions, affected by volumes • Significant efficiency gains (-2pp) and controlled CoR (+5bps) YoY • Profit up 15% QoQ driven by good performance of the main revenue lines, lower provisions and devaluation of the Argentine peso in Q4’23 Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 4,185 32.6 31.4 32.3 Net fee income 1,182 16.8 0.6 1.3 Total revenue 4,887 14.6 10.3 11.0 Operating expenses -1,829 17.0 5.9 6.1 Net operating income 3,058 13.3 13.2 14.1 LLPs -1,378 -11.0 10.0 11.9 Attributable profit 796 14.9 1.4 0.8 (*) € mn and % change in constant euros. (1) % change in current euros.

46Note: Q1’24 data and YoY changes (loans, deposits and mutual funds in constant euros). Brazil Chile Brasil and Chile Loans Deposits Mutual Funds Loans Deposits Mutual Funds Efficiency CoR RoTEEfficiency CoR RoTE €104bn +6% €89bn +11% €55bn +15% 33.0% -2.4pp 4.79% -5bps 15.4% +1.3pp €40bn +4% €28bn +9% €10bn +26% 42.5% +0.6pp 0.85% -10bps 9.7% -4.9pp • Growth in loans across all businesses except CIB (impacted by a more competitive market), in time deposits and in mutual funds • Profit increased strongly YoY, driven by NII (higher activity and lower cost of deposits) and efficiency gains, offsetting higher LLPs • Profit rose QoQ also due to strong NII growth, with lower costs and LLPs • Loans increased mainly due to mortgages, CIB and Payments. Double-digit growth in time deposits and mutual funds • Profit fell YoY despite the strong performance in NII (volumes and lower interest rates), impacted by growing costs, albeit below inflation, and a tick up in LLPs from low levels in previous years • In Q1, profit affected by lower NII (UF) and higher LLPs Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 2,630 5.8 20.5 24.9 Net fee income 846 -3.6 0.0 3.6 Total revenue 3,507 1.3 10.6 14.7 Operating expenses -1,156 -1.6 3.3 7.1 Net operating income 2,351 2.8 14.7 18.9 LLPs -1,163 -17.4 8.5 12.5 Attributable profit 561 14.5 15.4 19.7 (*) € mn and % change in constant euros. (1) % change in current euros. Underlying P&L* Q1'24 % Q4'23 % Q1'23 % Q1'23¹ NII 352 -7.9 12.1 -5.1 Net fee income 129 11.4 -0.8 -16.0 Total revenue 527 -4.2 2.7 -13.0 Operating expenses -224 -3.5 4.1 -11.9 Net operating income 303 -4.7 1.7 -13.9 LLPs -125 70.2 25.8 6.5 Attributable profit 90 -40.7 -28.9 -39.8 (*) € mn and % change in constant euros. (1) % change in current euros.

47Note: Q1’24 data and YoY changes (profit, loans, deposits and mutual funds in constant euros). In Argentina, given the strong ARS devaluation and high inflation and its effect on exchange rates, variations are in current euros. Argentina Argentina y Uruguay Uruguay, Peru and Colombia Loans Deposits Mutual Funds Uruguay Peru Colombia RoTEs € mn Attributable profit Efficiency CoR RoTE 49 Q1'24 +23% 29 Q1'24 +50% 8 Q1'24 +3% €5bn -10% €6bn -41% €4bn -13% 51.4% +1.6pp 5.43% +245bps 20.5% -9.4pp 23.4% +1.4pp 29.5% +6.5pp 14.6% -0.9pp • We are working to integrate our recent inorganic acquisitions • Profit YoY affected by hyperinflation adjustment and non-credit related provisions • QoQ comparison affected by strong peso devaluation in Q4 • Strong loan growth in Uruguay and on joint initiatives between CIB and Corporates in Peru and Colombia • Profit up YoY on the back of double-digit revenue growth in all three countries • High profitability: double-digit RoTEs Underlying P&L* Q1'24 Q4'23 % Q4'23 % Q1'23 NII 1,025 112 814.0 92.7 Net fee income 131 -50 — -4.2 Total revenue 555 -27 — 10.8 Operating expenses -286 6 — 14.4 Net operating income 270 -21 — 7.3 LLPs -35 -7 410.5 -18.5 Attributable profit 101 -20 — -27.2 (*) € mn and % change in current euros. (1) % change in current euros.

48 Appendix Investor Day Targets summary Detail by global business, region and country Reconciliation of underlying results to statutory results Glossary

49 Reconciliation of underlying results to statutory results (1) Includes exchange differences. Explanation of Q1’24 adjustments: • Temporary levy on revenue earned in Spain in the first quarter, totalling EUR 335 million, which was moved from total income to other gains (losses) and provisions. Explanation of Q1’23 adjustments: • Temporary levy on revenue earned in Spain in the first quarter, totalling EUR 224 million, which was moved from total income to other gains (losses) and provisions. • Income in Brazil related to the reversal of tax liabilities amounted to EUR 261 million (EUR 211 million recorded in net interest income and a positive impact of EUR 50 million in tax) and provisions to strengthen the balance sheet, which net of tax was EUR 261 million (EUR 474 million recorded in net loan-loss provisions and a positive impact of EUR 213 million in tax). Statutory results Adjustments Underlying results Statutory results Adjustments Underlying results Net interest income 11,983 — 11,983 10,396 (211) 10,185 Net fee income 3,240 — 3,240 3,043 — 3,043 Gains (losses) on financial transactions 1 623 — 623 715 — 715 Other operating income (801) 335 (466) (232) 224 (8) Total income 15,045 335 15,380 13,922 13 13,935 Administrative expenses and amortizations (6,547) — (6,547) (6,145) — (6,145) Net operating income 8,498 335 8,833 7,777 13 7,790 Net loan-loss provisions (3,125) — (3,125) (3,347) 474 (2,873) Other gains (losses) and provisions (790) (335) (1,125) (598) (224) (822) Profit before tax 4,583 — 4,583 3,832 263 4,095 Tax on profit (1,468) — (1,468) (967) (263) (1,230) Profit from continuing operations 3,115 — 3,115 2,865 — 2,865 Net profit from discontinued operations — — — — — — Consolidated profit 3,115 — 3,115 2,865 — 2,865 Non-controlling interests (263) — (263) (294) — (294) Profit attributable to the parent 2,852 — 2,852 2,571 — 2,571 January-March 2023January-March 2024

50 Appendix Investor Day Targets summary and our last step towards ONE SANTANDER Detail by global business, region and country Reconciliation of underlying results to statutory results Glossary

51 Glossary - Acronyms • A2A: account to account • ALCO: Assets and Liabilities Committee • AM: Asset management • AuMs: Assets under Management • bn: Billion • BNPL: Buy now, pay later • bps: Basis points • c.: Circa • CAL: Customer assets and liabilities • CET1: Common equity tier 1 • CHF: Swiss franc • CIB: Corporate & Investment Banking • CoE: Cost of equity • Consumer: Digital Consumer Bank • CoR: Cost of risk • Covid-19: Coronavirus Disease 19 • DCB Europe: Digital Consumer Bank Europe • DPS: Dividend per share • EPS: Earning per share • ESG: Environmental, social and governance • EV: Electric Vehicle • FL: Fully-loaded • FTE: Full time employee • FX: Foreign exchange • FY: Full year • IFRS 9: International Financial Reporting Standard 9, regarding financial instruments • LLPs: Loan-loss provisions • mn: million • NII: Net interest income • NIM: Net interest margin • NPL: Non-performing loans • NPS: Net promoter score • OEM: Original equipment manufacturer • Payments: PagoNxt and Cards • PB: Private Banking • PBT: Profit before tax • P&L: Profit and loss • pp: Percentage points • Ps: Per share • QoQ: Quarter-on-Quarter • Repos: Repurchase agreements • Retail: Retail & Commercial Banking • RoE: Return on equity • RoRWA: Return on risk-weighted assets • RoTE: Return on tangible equity • RWA: Risk-weighted assets • SAM: Santander Asset Management • SBB: share buybacks • SME: Small and Medium Enterprises • TNAV: Tangible net asset value • TPV: Total Payments Volume • YoY: Year-on-Year • YTD: Year to date • Wealth: Wealth Management & Insurance

52 Glossary - Definitions Notes: The averages for the RoTE and RoRWA denominators are calculated using the monthly average over the period, which we believe should not differ materially from using daily balances. The risk-weighted assets included in the denominator of the RoRWA metric are calculated in line with the criteria laid out in the CRR (Capital Requirements Regulation). PROFITABILITY AND EFFICIENCY • RoTE: Return on tangible capital: Group attributable profit / average of: net equity (excluding minority interests) – intangible assets (including goodwill) • RoRWA: Return on risk-weighted assets: consolidated profit / average risk-weighted assets • Efficiency: Operating expenses / total income. Operating expenses defined as general administrative expenses + amortisations VOLUMES • Loans: Gross loans and advances to customers (excl. reverse repos) • Customer funds: Customer deposits excluding repos + marketed mutual funds CREDIT RISK • NPL ratio: Credit impaired loans and advances to customers, customer guarantees and customer commitments granted / Total risk. Total risk is defined as: Total loans and advances and guarantees to customers (including credit impaired assets) + contingent liabilities granted that are credit impaired • NPL coverage ratio: Total allowances to cover impairment losses on loans and advances to customers, customer guarantees and customer commitments granted / Credit impaired loans and advances to customers, customer guarantees and customer commitments granted • Cost of risk: Provisions to cover losses due to impairment of loans in the last 12 months / average customer loans and advances of the last 12 months CAPITALIZATION • Tangible net asset value per share – TNAVps: Tangible stockholders' equity / number of shares (excluding treasury shares). Tangible stockholders' equity calculated as shareholders equity + accumulated other comprehensive income - intangible assets ESG METRICS • Women in leadership positions = Percentage of women in senior executive positions over total headcount. This segment corresponds to less than 1% of the total workforce • Equal pay gap = The equal pay gap measures differences in remuneration between women and men in the same job at the same level. • For financial ESG metrics, please see ‘Alternative Performance Measures’ section of the Quarterly Financial Report.

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SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. Banco Santander, S.A. Date:    30 April 2024 By: /s/ José García Cantera Name: José García Cantera Title: Chief Financial Officer