The ATT WiFi calling service supports international roaming

When roaming internationally on ATT Wi-fi Calling, will I be charged for incoming calls? 

If you have disabled your phone by putting it in airplane mode, and turning Wi-Fi back on, Wi-Fi calls and text are as if you are in the USA. 

As of right now, I am traveling to Republic of Ireland on an AT&T Prepaid Elite Unlimited plan.

There is no such thing as a prepaid elite plan.   If you are a prepaid user, the $35 prepaid add-on gives you 5 GB of data for one week and does work in the United Kingdom. It is not an automatic charge you must prepay the $35 in order to use service at all.

The elite plan is a postpaid plan. If you are on postpaid service, the international day pass covers all usage as if you were in the United States for $10 a day charge but is capped at 10 charges per bill cycle. You must add international day pass to your line for this coverage. 

I have put my phone in airplane mode since I haven't purchased any international day passes. My cell phone can receive incoming calls after I enable Wi-Fi Calling. 

See my first reply

Could you please let me know if I will be charged for picking up these calls and talking to the other party. Your advice would be greatly appreciated. 

I don't want to mess up this deal with AT&T because their charges are outrageous.

See first reply 

Wi-Fi calls and text are as if you are in the USA. 

In other words, you won’t be charged.