<?xml version="1.0" encoding="US-ASCII"?>
<!-- Generated by CompSci Transform (tm) - http://www.compsciresources.com -->
<!-- Created: Mon Oct 06 21:00:38 UTC 2025 -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
  <roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#IndividualsOnly" roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly"/>
  <roleRef xlink:type="simple" xlink:href="iren-20251119.xsd#iren_r_AdditionalDimensions" roleURI="http://www.iren.com/role/AdditionalDimensions"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member"/>
<!-- [WMV6][8KLyXP0u5p/J3dN1mvdp9wLBc74FwRkY3YKeStW7zocjHSuFxjyQcyca8d/yK/Xhm+k+IHmwR2QWV+nFipL8ChMWygo/fzDw2bSy/dMx5Fig1Dkkf5Ohq8mNRUdExQK+EKEenC0zn5VBxk5N6/YM5nGKPSrABohw802XLouQzWbKAMSAkF3U7cZLGqx6aIeKA04/N/EGTQqBFGZo91CAsd/3+zbe/35dfIDktu8GIjAETxKYtlWzOoxfDsfiB/zYzSlmelu7CpkCE4PyoYmxESX9JDWx4HZ3a914BszXoLMpCqC5Q36TzIxKXztOHpk2UM4I3+5VghxiI0XiV9G1kZshpMAiRF/vog86KyL+mh64] CSR-->
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all"/>
  <definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="extended">
    <loc xlink:type="locator" xlink:label="ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllIndividualsMember"/>
    <loc xlink:type="locator" xlink:label="iren_MrWilliamRobertsMember" xlink:href="iren-20251119.xsd#iren_MrWilliamRobertsMember"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllIndividualsMember" xlink:to="iren_MrWilliamRobertsMember" order="2" xbrldt:closed="true"/>
    <loc xlink:type="locator" xlink:label="iren_MrDanielRobertsMember" xlink:href="iren-20251119.xsd#iren_MrDanielRobertsMember"/>
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_AllIndividualsMember" xlink:to="iren_MrDanielRobertsMember" order="4" xbrldt:closed="true"/>
  </definitionLink>
  <definitionLink xlink:role="http://www.iren.com/role/AdditionalDimensions" xlink:type="extended"/>
</linkbase>
