<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
  <headerData>
    <submissionType>144</submissionType>
    <filerInfo>
      <filer>
        <filerCredentials>
          <cik>0001379586</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <issuerInfo>
      <issuerCik>0001637207</issuerCik>
      <issuerName>Planet Fitness Inc </issuerName>
      <secFileNumber>001-37534</secFileNumber>
      <issuerAddress>
        <com:street1>4 Liberty Lane West</com:street1>
        <com:city>Hampton</com:city>
        <com:stateOrCountry>NH</com:stateOrCountry>
        <com:zipCode>03842</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>603-750-0001</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Cambria Dunaway</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>Board Member</relationshipToIssuer>
      </relationshipsToIssuer>
    </issuerInfo>
    <securitiesInformation>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>UBS Financial Services Inc</name>
        <address>
          <com:street1>1000 Harbor Blvd</com:street1>
          <com:street2>3rd Floor</com:street2>
          <com:city>Weehawken</com:city>
          <com:stateOrCountry>NJ</com:stateOrCountry>
          <com:zipCode>07086</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>3000</noOfUnitsSold>
      <aggregateMarketValue>276000</aggregateMarketValue>
      <noOfUnitsOutstanding>84330138</noOfUnitsOutstanding>
      <approxSaleDate>03/10/2025</approxSaleDate>
      <securitiesExchangeName>NYSE</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>04/01/2019</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>179</amountOfSecuritiesAcquired>
      <paymentDate>04/01/2019</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>07/01/2019</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>166</amountOfSecuritiesAcquired>
      <paymentDate>07/01/2019</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>01/02/2020</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>166</amountOfSecuritiesAcquired>
      <paymentDate>01/02/2020</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>01/04/2021</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>219</amountOfSecuritiesAcquired>
      <paymentDate>01/04/2021</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>04/01/2021</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>206</amountOfSecuritiesAcquired>
      <paymentDate>04/01/2021</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>07/01/2021</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>215</amountOfSecuritiesAcquired>
      <paymentDate>07/01/2021</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>10/01/2021</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>195</amountOfSecuritiesAcquired>
      <paymentDate>10/01/2021</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>10/09/2021</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>1183</amountOfSecuritiesAcquired>
      <paymentDate>10/09/2021</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>01/03/2022</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>176</amountOfSecuritiesAcquired>
      <paymentDate>01/03/2022</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>04/04/2022</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>192</amountOfSecuritiesAcquired>
      <paymentDate>04/04/2022</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Class A common stock</securitiesClassTitle>
      <acquiredDate>07/01/2022</acquiredDate>
      <natureOfAcquisitionTransaction>RSU</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>103</amountOfSecuritiesAcquired>
      <paymentDate>07/01/2022</paymentDate>
      <natureOfPayment>N/A</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <remarks>Dunaway Living Trust is the seller. Cambria Dunaway is the board member of Planet Fitness Inc and also the trustee of the Dunaway Living Trust.  Shareholder didn't pay for the shares. </remarks>
    <noticeSignature>
      <noticeDate>03/10/2025</noticeDate>
      <signature>/s/ UBS Financial Services Inc, as attorney-in-fact for Cambria Dunaway</signature>
    </noticeSignature>
  </formData>
</edgarSubmission>
