When using a U.S. cell phone in Ireland is best option to switch to a local SIM card in the Republic? Will same SIM card also work in Northern Ireland?
In my last trip, I used GiffGaff for a esim, and used a "local" UK number. The EU changed the rules so GiffGaff only works IF you connect in the UK (momentarily), then it works in the EU for 60 days.
This trip (leaving for Dublin in two hours), I pre-purchased a "data only" esim. Many vendors - I went with Maya. They assure me that I can make calls/texts with just their data plan if my carrier supports wifi calling (which I use at home). If it turns out they fibbed, I'll go to the Three Store near our hotel and get an esim with a +353 number.
I don't use texting/calling very much, so it is no big deal if I can't talk to home. BUT there are no vendors that will ship a full esim to a US address, so it was a choice between "try the data esim" or "get a new phone number upon arrival in Dublin". The latter is clumsier and I do worry about unexpected multi-level--authentication issues with the new number if I don't know it before departure.
I'll report about the wifi calling ability in a day or two.
well, a data esim didn't work for me to use wifi calling/text for no obvious reason, despite wifi calling working at home. maybe a home carrier problem (USCellular) or Maya's expecting me to use WhatsApp for those functions. If my home Sim was enabled, I just got warnings about daily charges of $15. so I ended up going to a Three Store to get an IE local number for 20 euros. disappointed...
WiFi calling requires a valid phone number. You could have turn off the data only eSIM/SIM and turn on your US phone number eSIM/SIM while connected to WiFi and WiFi calling will be enabled. Remember that with your US number WiFi calling to any overseas number will incur international long distance charges . WiFi calling back to the US is free.
Orange eSIM has a French number that includes unlimited minutes and texting within the EU. There are multiple data package available that include international calling minutes and texting. The eSIM QR code can be emailed to you. I have used Orange eAIM on my last 5 trips to Europe
My phone plan does not work internationally and so I purchased the O2 Travel ( 20 GB ) plan from eSIM.net before leaving for Ireland earlier this month. If you have a eSIM slot available, I recommend purchasing this plan, or a similar plan. It comes with a UK phone number, which I used with no problem. The 20 GB of data is good for 30 days (I only needed 15 days, but the plan was very reasonably priced so I purchased this one). Once purchased, a QR code is sent immediately, with clear instructions. With this plan, do not install and activate at home. When you get to the Dublin airport (or anywhere with wifi in Dublin), use wifi to install/activate the eSim. It takes a few minutes and you are good to go. For just over two weeks, I used well under 1.5 GB.
Yes, this plan should work in Northern Ireland based on the eSIM information:
"Your plan includes unlimited UK-to-UK calls and also local calls and inbound texts within the country that you are roaming in (500 minutes for O2 Travel). Calls and inbound texts within the EU are included."
All the best!