Vodafone Ireland have recently started issuing ESims in ROI. I think Three should follow suit soon, handsets such as iPhone only allow dual sim using one of these
@Add_10861You make a good point. There are precedents to this when Apple moved to nano-SIM with the iPhone 5 in 2012, and various networks initially refused to supply nano-SIMs to prepaid customers, which was quite relevant for travelling before the EU abolished roaming surcharges. At least it was possible to cut a micro-SIM to a nano-SIM, for which SIM cutters were widely sold on eBay. The same isn't true of eSIM.