Will my HotelESIM internet work on the Aran Islands ferry in Ireland?

Yes, your HotelESIM should provide internet signal while on the ferry to the Aran Islands, especially as you depart from Rossaveel and once you are closer to Inis Mór or the other islands. There might be brief periods during the open water crossing in Galway Bay where the signal could be intermittent. However, for most of the journey and certainly upon arrival, you can expect reliable connectivity, allowing you to plan your island explorations.