UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Amendment No. 2)*

Under the Securities Exchange Act of 1934

Navios Maritime Midstream Partners L.P.

(Name of Issuer)

Common Units representing limited partner interests

(Title of Class of Securities)

Y62134104

(CUSIP Number)

Vasiliki Papaefthymiou

Secretary

Navios Maritime Acquisition Corporation

7 Avenue de Grande Bretagne, Office 11B2

Monte Carlo, MC 98000 Monaco

(011) + (377) 9798-2140

With a copy to:

Philip Richter

Fried, Frank, Harris, Shriver & Jacobson LLP

One New York Plaza

New York, New York 10004

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

June 28, 2018

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box.  ☐.

Note. Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7(b) for the other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Explanatory Note

Pursuant to Rule 13(d)-2 promulgated under the Securities Exchange Act of 1934, as amended, this Schedule 13D/A (this “Amendment No. 2”) filed on June 28, 2018 amends the Schedule 13D/A filed on December 1, 2017 (“Amendment No. 1”) which amended the Schedule 13D filed on March 10, 2015 (the “Original Schedule 13D” and together with Amendment No. 1 and this Amendment No. 2, the “Schedule 13D”). This Amendment No. 2 relates to the common units of the Issuer. Capitalized terms used herein but not otherwise defined shall have the meaning ascribed to such term in the Original Schedule 13D.

Item 3. Source and Amount of Funds or Other Consideration.

Item 3 of the Schedule 13D is hereby supplemented to include the following:

On June 18, 2018, 1,592,920 series A subordinated units automatically converted into Common Units on a one-for-one basis in accordance with the terms of the Partnership Agreement.

Item 4 of this Amendment No. 2 is incorporated by reference.

Item 4. Purpose of Transaction.

Item 4 of the Schedule 13D is hereby supplemented to include the following:

On June 28, 2018, the Reporting Person submitted a letter (the “Proposal Letter”) to the board of directors of the Issuer for the combination of the Issuer with the Reporting Person by means of a merger in which each common unit of the Issuer not held by the Reporting Person would be exchanged for 6.292 newly-issued shares of common stock of the Reporting Person. The Reporting Person does not intend to update the Schedule 13D by making further disclosure regarding the subject matter of the Proposal Letter until a definitive agreement has been reached, or unless disclosure is otherwise required under applicable securities laws. A copy of the Proposal Letter is attached hereto as Exhibit D and the information in the Proposal Letter is incorporated herein by reference.

In addition, on June 28, 2018, the Reporting Person issued a press release announcing the proposal set forth in the Proposal Letter. A copy of the press release issued by the Reporting person is attached hereto as Exhibit E and the information in the press release is incorporated herein by reference.

Item 5 Interest in Securities of the Issuer.

Clause (a) of Item 5 of the Schedule 13D is hereby amended and restated as follows:

The Reporting Person beneficially owns 12,178,304 Common Units, representing 58.1% of the outstanding Common Units in the Issuer. In addition, the reporting person beneficially owns 427,499 General Partner Units through its ownership of the General Partner.

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer.

Item 6 of Schedule 13D is hereby supplemented to incorporate by reference, Item 4 of this Amendment No. 2.

Item 7. Material to be Filed as Exhibits.

Item 7 of the Schedule 13D is hereby supplemented to include the following:

Signature

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

EXHIBIT INDEX

Exhibit D

June 28, 2018

VIA EMAIL

Board of Directors

Navios Maritime Midstream Partners L.P.

7 Avenue de Grande Bretagne, Office 11B2

Monte Carlo, MC, 98000 Monaco

Dear Members of the Board:

The Board of Directors of Navios Maritime Acquisition Corporation (“NNA”) has authorized us to propose a transaction in which Navios Maritime Midstream Partners L.P. (“NAP”) would be combined with NNA by means of a merger in which each common unit of NAP not held by NNA would be exchanged for 6.292 newly issued shares of common stock of NNA.

We believe that our proposal should be well received by NAP’s unit holders. The proposal reflects a 1% premium to the NAP unit holders, based on the respective closing prices of NAP units and NNA shares on June 28, 2018, which we believe is consistent with premia paid in recent MLP recombination transactions. The share-for-unit exchange would also provide NAP unit holders with significant participation in the overall more diversified entity on a tax-free basis.

By combining the two companies, we would expand appeal to a broader range of investors by:

Through these benefits, we believe that the investor appeal will be enhanced and the combined entity will have an opportunity to increase value to stakeholders. A merger of NNA and NAP seems to be the most feasible option to enable NAP to unlock value and establish a new growth trajectory for its unitholders.    

Any combination between NNA and NAP would be subject to receipt of the necessary approvals under NAP’s limited partnership agreement. In accordance with its legal obligations, NNA will file promptly an amendment to its Schedule 13D, including a copy of this letter.

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We look forward to working with the Conflicts Committee and its independent legal and financial advisors to negotiate and complete a mutually acceptable transaction. We are available at your convenience to discuss any aspects of our proposal.

Please be aware that this proposal is an expression of interest only, and we reserve the right to withdraw or modify our proposal in any manner at any time for any reason or for no reason at all. No legal obligation with respect to a transaction will arise unless and until execution of mutually acceptable definitive documentation.

Should you have any questions, please do not hesitate to contact me.

Sincerely,

Navios Maritime Acquisition Corporation

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Exhibit E

Navios Maritime Acquisition Corporation

Announces

Offer to Acquire

Outstanding Units of Navios Maritime Midstream Partners L.P.

MONACO, June 28, 2018 (GLOBE NEWSWIRE) — Navios Maritime Acquisition Corporation (“Navios Acquisition”) (NYSE:NNA), an owner and operator of tanker vessels, announced today that it has submitted a proposal to the board of directors of Navios Maritime Midstream Partners L.P. (“Navios Midstream”) (NYSE:NAP) to acquire the publicly held units of Navios Midstream not already owned by Navios Acquisition in a stock for units exchange.

Subject to negotiation and execution of a definitive agreement, Navios Acquisition is proposing consideration of 6.292 Navios Acquisition shares for each outstanding publicly held unit of Navios Midstream as part of a transaction that would be structured as a merger of Navios Midstream with Navios Acquisition. The proposed consideration represents a value of $3.838 per common unit of Navios Midstream based on the closing price of Navios Acquisition’s shares as of June 28, 2018. The proposed transaction is expected to be a tax-free exchange to Navios Midstream’s unit holders for US federal income tax purposes.

The proposed transaction is subject to the negotiation and execution of a definitive agreement, approval of the board of directors of Navios Acquisition and the necessary approvals under Navios Midstream’s limited partnership agreement. The consummation of the proposed transaction would be subject to customary closing conditions. There can be no assurance that any such approvals will be forthcoming, that a definitive agreement will be executed, or that any transaction will be consummated.

This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities. This communication is not a substitute for any documents that may be filed with the SEC or sent to equity holders in connection with the proposed transaction. Equity holders are urged to read those documents, which will contain important information.

About Navios Maritime Acquisition Corporation

Navios Acquisition (NYSE:NNA) is an owner and operator of tanker vessels focusing on the transportation of petroleum products (clean and dirty) and bulk liquid chemicals. For more information about Navios Acquisition, please visit our website:
www.navios-acquisition.com.

Forward-Looking Statements

This press release contains forward-looking statements (as defined in Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended) concerning future events and expectations, including with respect to Navios Acquisition’s stock repurchases, future dividends, future cash flow generation and Navios Acquisition’s growth strategy and measures to implement such strategy; including expected vessel acquisitions and entering into further time charters. Words such as “may,” “expects,” “intends,” “plans,” “believes,” “anticipates,” “hopes,” “estimates,” and variations of such words and similar expressions are intended to identify forward-looking statements. Such statements include comments regarding expected revenue and time charters. These forward-looking statements are based on the information available to, and the expectations and assumptions

deemed reasonable by, Navios Acquisition at the time these statements were made. Although Navios Acquisition believes that the expectations reflected in such forward-looking statements are reasonable, no assurance can be given that such expectations will prove to have been correct. These statements involve known and unknown risks and are based upon a number of assumptions and estimates which are inherently subject to significant uncertainties and contingencies, many of which are beyond the control of Navios Acquisition. Actual results may differ materially from those expressed or implied by such forward-looking statements. Factors that could cause actual results to differ materially include, but are not limited to, the creditworthiness of our charterers and the ability of our contract counterparties to fulfill their obligations to us, tanker industry trends, including charter rates and vessel values and factors affecting vessel supply and demand, the aging of our vessels and resultant increases in operation and dry docking costs, the loss of any customer or charter or vessel, our ability to repay outstanding indebtedness, to obtain additional financing and to obtain replacement charters for our vessels, in each case, at commercially acceptable rates or at all, increases in costs and expenses, including but not limited to: crew wages, insurance, provisions, port expenses, lube oil, bunkers, repairs, maintenance and general and administrative expenses, the expected cost of, and our ability to comply with, governmental regulations and maritime self-regulatory organization standards, as well as standard regulations imposed by our charterers applicable to our business, potential liability from litigation and our vessel operations, including discharge of pollutants, general domestic and international political conditions, competitive factors in the market in which Navios Acquisition operates; risks associated with operations outside the United States; and other factors listed from time to time in the Navios Acquisition’s filings with the U.S. Securities and Exchange Commission, including its annual and interim reports filed on Form 20-F and Form 6-K. Navios Acquisition expressly disclaims any obligations or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in Navios Acquisition’s expectations with respect thereto or any change in events, conditions or circumstances on which any statement is based. Navios Acquisition makes no prediction or statement about the performance of its common stock.

Investor Relations Contact

Navios Maritime Acquisition Corporation

+1.212.906.8644

info@navios-acquisition.com