<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/nport" xmlns:com="http://www.sec.gov/edgar/common" xmlns:ncom="http://www.sec.gov/edgar/nportcommon" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sec.gov/edgar/nport eis_NPORT_Filer.xsd">
	<headerData>
		<submissionType>NPORT-P</submissionType>
		<isConfidential>false</isConfidential>
		<filerInfo>

			<filer>
				<issuerCredentials>
					<cik>0000076721</cik>
					<ccc>XXXXXXXX</ccc>
				</issuerCredentials>
			</filer>

			<seriesClassInfo>
				<seriesId>S000011971</seriesId>
				<classId>C000043250</classId>
				<classId>C000043251</classId>
			</seriesClassInfo>


		</filerInfo>
	</headerData>
	<formData>
		<genInfo>
			<regName>IMPAX FUNDS SERIES TRUST I</regName>
			<regFileNumber>811-02064</regFileNumber>
			<regCik>0000076721</regCik>
			<regLei>549300TD5R23SWU72456</regLei>
			<regStreet1>30 Penhallow St.</regStreet1>
			<regStreet2>Suite 400</regStreet2>
			<regCity>Portsmouth</regCity>
			<regStateConditional regCountry="US" regState="US-NH"/>
			<regZipOrPostalCode>03801</regZipOrPostalCode>
			<regPhone>800-767-1729</regPhone>
			<seriesName>Impax Sustainable Allocation Fund</seriesName>
			<seriesId>S000011971</seriesId>
			<seriesLei>5493005QNFIONEGYS209</seriesLei>
			<repPdEnd>2023-12-31</repPdEnd>
			<repPdDate>2023-09-30</repPdDate>
			<isFinalFiling>N</isFinalFiling>
		</genInfo>
		<fundInfo>
			<totAssets>2131807025.5</totAssets>
			<totLiabs>358212.73</totLiabs>
			<netAssets>2131448812.77</netAssets>
			<assetsAttrMiscSec>0</assetsAttrMiscSec>
			<assetsInvested>0</assetsInvested>
			<amtPayOneYrBanksBorr>0</amtPayOneYrBanksBorr>
			<amtPayOneYrCtrldComp>0</amtPayOneYrCtrldComp>
			<amtPayOneYrOthAffil>0</amtPayOneYrOthAffil>
			<amtPayOneYrOther>0</amtPayOneYrOther>
			<amtPayAftOneYrBanksBorr>0</amtPayAftOneYrBanksBorr>
			<amtPayAftOneYrCtrldComp>0</amtPayAftOneYrCtrldComp>
			<amtPayAftOneYrOthAffil>0</amtPayAftOneYrOthAffil>
			<amtPayAftOneYrOther>0</amtPayAftOneYrOther>
			<delayDeliv>0</delayDeliv>
			<standByCommit>0</standByCommit>
			<liquidPref>0</liquidPref>
			<cshNotRptdInCorD>0</cshNotRptdInCorD>
			<isNonCashCollateral>N</isNonCashCollateral>
			<returnInfo>
				<monthlyTotReturns>
					<monthlyTotReturn classId="C000043250" rtn1="-3.99" rtn2="-2.08" rtn3="1.74"/>
					<monthlyTotReturn classId="C000043251" rtn1="-3.95" rtn2="-2.04" rtn3="1.75"/>
				</monthlyTotReturns>
				<monthlyReturnCats/>
				<othMon1 netRealizedGain="-35641.18" netUnrealizedAppr="-90671156.64"/>
				<othMon2 netRealizedGain="1544012.25" netUnrealizedAppr="-51005649.61"/>
				<othMon3 netRealizedGain="7112525.77" netUnrealizedAppr="30036928.31"/>
			</returnInfo>
			<mon1Flow redemption="18868858.1" reinvestment="0" sales="7580433.2"/>
			<mon2Flow redemption="19451536.49" reinvestment="0" sales="7439361.97"/>
			<mon3Flow redemption="16927649.12" reinvestment="0" sales="7774413.51"/>
		</fundInfo>
		<invstOrSecs>
			<invstOrSec>
				<name>IMPAX CORE BOND FUND</name>
				<lei>N/A</lei>
				<title>IMPAX CORE BOND FUND INST</title>
				<cusip>704223460</cusip>
				<identifiers>
					<isin value="US7042234606"/>
					<ticker value="PXBIX"/>
				</identifiers>
				<balance>92045791.601</balance>
				<units>NS</units>
				<curCd>USD</curCd>
				<valUSD>774105107.36</valUSD>
				<pctVal>36.318259332439</pctVal>
				<payoffProfile>Long</payoffProfile>
				<assetCat>EC</assetCat>
				<issuerCat>RF</issuerCat>
				<invCountry>US</invCountry>

				<isRestrictedSec>N</isRestrictedSec>

				<fairValLevel>1</fairValLevel>
				<securityLending>
					<isCashCollateral>N</isCashCollateral>
					<isNonCashCollateral>N</isNonCashCollateral>
					<isLoanByFund>N</isLoanByFund>
				</securityLending>
			</invstOrSec>
			<invstOrSec>
				<name>IMPAX ELLEVATE GLOBAL WOMEN S</name>
				<lei>N/A</lei>
				<title>IMPAX ELLEV GL WMN LDR INST</title>
				<cusip>70422T109</cusip>
				<identifiers>
					<isin value="US70422T1097"/>
					<ticker value="PXWIX"/>
				</identifiers>
				<balance>2095599.749</balance>
				<units>NS</units>
				<curCd>USD</curCd>
				<valUSD>59284516.9</valUSD>
				<pctVal>2.781418748825</pctVal>
				<payoffProfile>Long</payoffProfile>
				<assetCat>EC</assetCat>
				<issuerCat>RF</issuerCat>
				<invCountry>US</invCountry>

				<isRestrictedSec>N</isRestrictedSec>

				<fairValLevel>1</fairValLevel>
				<securityLending>
					<isCashCollateral>N</isCashCollateral>
					<isNonCashCollateral>N</isNonCashCollateral>
					<isLoanByFund>N</isLoanByFund>
				</securityLending>
			</invstOrSec>
			<invstOrSec>
				<name>IMPAX GLOBAL ENVIRONMENTAL MAR</name>
				<lei>N/A</lei>
				<title>IMPAX GLBL ENVIRON MRKT INST</title>
				<cusip>704223775</cusip>
				<identifiers>
					<isin value="US7042237757"/>
					<ticker value="PGINX"/>
				</identifiers>
				<balance>2656702.736</balance>
				<units>NS</units>
				<curCd>USD</curCd>
				<valUSD>52868384.45</valUSD>
				<pctVal>2.480396626616</pctVal>
				<payoffProfile>Long</payoffProfile>
				<assetCat>EC</assetCat>
				<issuerCat>RF</issuerCat>
				<invCountry>US</invCountry>

				<isRestrictedSec>N</isRestrictedSec>

				<fairValLevel>1</fairValLevel>
				<securityLending>
					<isCashCollateral>N</isCashCollateral>
					<isNonCashCollateral>N</isNonCashCollateral>
					<isLoanByFund>N</isLoanByFund>
				</securityLending>
			</invstOrSec>
			<invstOrSec>
				<name>IMPAX GLOBAL OPPORTUNITIES FUN</name>
				<lei>N/A</lei>
				<title>IMPAX GLOBAL OPPORTUNIT INST</title>
				<cusip>704223429</cusip>
				<identifiers>
					<isin value="US7042234291"/>
					<ticker value="PXGOX"/>
				</identifiers>
				<balance>4095396.375</balance>
				<units>NS</units>
				<curCd>USD</curCd>
				<valUSD>58605122.13</valUSD>
				<pctVal>2.749543961782</pctVal>
				<payoffProfile>Long</payoffProfile>
				<assetCat>EC</assetCat>
				<issuerCat>RF</issuerCat>
				<invCountry>US</invCountry>

				<isRestrictedSec>N</isRestrictedSec>

				<fairValLevel>1</fairValLevel>
				<securityLending>
					<isCashCollateral>N</isCashCollateral>
					<isNonCashCollateral>N</isNonCashCollateral>
					<isLoanByFund>N</isLoanByFund>
				</securityLending>
			</invstOrSec>
			<invstOrSec>
				<name>IMPAX GLOBAL SUSTAINABLE INFRA</name>
				<lei>N/A</lei>
				<title>IMPAX GLBL SUST INFRA FD INS</title>
				<cusip>704223445</cusip>
				<identifiers>
					<isin value="US7042234457"/>
					<ticker value="PXDIX"/>
				</identifiers>
				<balance>8076802.663</balance>
				<units>NS</units>
				<curCd>USD</curCd>
				<valUSD>67522070.26</valUSD>
				<pctVal>3.16789546413</pctVal>
				<payoffProfile>Long</payoffProfile>
				<assetCat>EC</assetCat>
				<issuerCat>RF</issuerCat>
				<invCountry>US</invCountry>

				<isRestrictedSec>N</isRestrictedSec>

				<fairValLevel>1</fairValLevel>
				<securityLending>
					<isCashCollateral>N</isCashCollateral>
					<isNonCashCollateral>N</isNonCashCollateral>
					<isLoanByFund>N</isLoanByFund>
				</securityLending>
			</invstOrSec>
			<invstOrSec>
				<name>IMPAX HIGH YIELD BOND FUND</name>
				<lei>N/A</lei>
				<title>IMPAX HIGH YIELD BOND INST</title>
				<cusip>704223809</cusip>
				<identifiers>
					<isin value="US7042238094"/>
					<ticker value="PXHIX"/>
				</identifiers>
				<balance>16855888.752</balance>
				<units>NS</units>
				<curCd>USD</curCd>
				<valUSD>96078565.89</valUSD>
				<pctVal>4.507664707422</pctVal>
				<payoffProfile>Long</payoffProfile>
				<assetCat>EC</assetCat>
				<issuerCat>RF</issuerCat>
				<invCountry>US</invCountry>

				<isRestrictedSec>N</isRestrictedSec>

				<fairValLevel>1</fairValLevel>
				<securityLending>
					<isCashCollateral>N</isCashCollateral>
					<isNonCashCollateral>N</isNonCashCollateral>
					<isLoanByFund>N</isLoanByFund>
				</securityLending>
			</invstOrSec>
			<invstOrSec>
				<name>IMPAX INTERNATIONAL SUSTAINABL</name>
				<lei>N/A</lei>
				<title>IMPAX INTL SUSTAIN ECON INST</title>
				<cusip>704223742</cusip>
				<identifiers>
					<isin value="US7042237427"/>
					<ticker value="PXNIX"/>
				</identifiers>
				<balance>11781804.513</balance>
				<units>NS</units>
				<curCd>USD</curCd>
				<valUSD>106154058.66</valUSD>
				<pctVal>4.980371005112</pctVal>
				<payoffProfile>Long</payoffProfile>
				<assetCat>EC</assetCat>
				<issuerCat>RF</issuerCat>
				<invCountry>US</invCountry>

				<isRestrictedSec>N</isRestrictedSec>

				<fairValLevel>1</fairValLevel>
				<securityLending>
					<isCashCollateral>N</isCashCollateral>
					<isNonCashCollateral>N</isNonCashCollateral>
					<isLoanByFund>N</isLoanByFund>
				</securityLending>
			</invstOrSec>
			<invstOrSec>
				<name>IMPAX LARGE CAP FUND</name>
				<lei>N/A</lei>
				<title>IMPAX LARGE CAP FUND INST</title>
				<cusip>704223486</cusip>
				<identifiers>
					<isin value="US7042234861"/>
					<ticker value="PXLIX"/>
				</identifiers>
				<balance>66593074.592</balance>
				<units>NS</units>
				<curCd>USD</curCd>
				<valUSD>813101440.77</valUSD>
				<pctVal>38.147828645873</pctVal>
				<payoffProfile>Long</payoffProfile>
				<assetCat>EC</assetCat>
				<issuerCat>RF</issuerCat>
				<invCountry>US</invCountry>

				<isRestrictedSec>N</isRestrictedSec>

				<fairValLevel>1</fairValLevel>
				<securityLending>
					<isCashCollateral>N</isCashCollateral>
					<isNonCashCollateral>N</isNonCashCollateral>
					<isLoanByFund>N</isLoanByFund>
				</securityLending>
			</invstOrSec>
			<invstOrSec>
				<name>IMPAX SMALL CAP FUND</name>
				<lei>N/A</lei>
				<title>IMPAX SMALL CAP FUND INST</title>
				<cusip>704223817</cusip>
				<identifiers>
					<isin value="US7042238177"/>
					<ticker value="PXSIX"/>
				</identifiers>
				<balance>5641695.316</balance>
				<units>NS</units>
				<curCd>USD</curCd>
				<valUSD>82989338.1</valUSD>
				<pctVal>3.893564677828</pctVal>
				<payoffProfile>Long</payoffProfile>
				<assetCat>EC</assetCat>
				<issuerCat>RF</issuerCat>
				<invCountry>US</invCountry>

				<isRestrictedSec>N</isRestrictedSec>

				<fairValLevel>1</fairValLevel>
				<securityLending>
					<isCashCollateral>N</isCashCollateral>
					<isNonCashCollateral>N</isNonCashCollateral>
					<isLoanByFund>N</isLoanByFund>
				</securityLending>
			</invstOrSec>
		</invstOrSecs>
		<signature>
			<ncom:dateSigned>2023-11-21</ncom:dateSigned>
			<ncom:nameOfApplicant>IMPAX FUNDS SERIES TRUST I</ncom:nameOfApplicant>
			<ncom:signature>/s/ Alicia DuBois</ncom:signature>
			<ncom:signerName>Alicia DuBois</ncom:signerName>
			<ncom:title>Treasurer</ncom:title>
		</signature>
	</formData>
	<documents>XXXX</documents>
</edgarSubmission>
