Foreign Esim Provider While Traveling / Wi-Fi Calling & Texting

1. Would I need to remove my physical sim card from my phone while using the local e-sim?

No.

If not, what settings should I be changing on my phone or account?

Each Sim is listed in the settings on your phone. You can actually see the e-sim now even though it's not in use... Look in settings under mobile network

1. How do I ensure that I don't get charged for international roaming? 

Turn off data roaming on the AT&T number.  Don't answer calls or send text. 

You can turn off the AT&T number when you switch Sims.  

FYI, there is no charge for incoming text over cellular 

1. Does Wi-Fi Calling still work when I'm on a Wi-Fi network,

Yes, if you switch to the AT&T sim

1. and will I be able to receive or send ATT USA text messages?

Yes.  If you switch over to your AT&T sim

International day pass does not charge you unless you use the service. Your intention is to use a foreign SIM card and not use your AT&T phone except over Wi-Fi calling. The plan is solid.

However, I encourage people to add international day pass as a safety net. It limits your charges to $10 per day on any day you use your AT&T phone number rather than high roaming charges.  There is also a cap of $100 per bill cycle. 

If you follow your plan you will not incur any charges from AT&T for using roaming on your phone. But if something goes wrong and you are stuck without Wi-Fi calling and must call the USA, it's there. 

 Someone I know was in an accident overseas, they did not have access to Wi-Fi at the hospital or at the police station to make wifi calls home. 

Reminder that to use a non AT&T eSIM/SIM your phone has to be unlocked. 

Just got back from Italy and uses Wi-Fi calling to call/text back to the US.  I turned off the AT&T SIM and used the Italian eSIM when not using Wi-Fi calling. Tuned off Italian SIM and turned on the AT&T SIM to use Wi-Fi calling. Any text messages or voice mail to my AT&T number that were queued up came in when connected to Wi-Fi. 

Thanks for the help formerlyknownas and Fl_retire! I appreciate you sharing your knowledge on this. 

Forgot to mention that I received alerts from my apps (bank, credit cards, etc) when using the Italian SIM.

@Fl_retire , questions on your comments above about eSIMs (Airelo) and ATT.  

1. Doesn't one have to turn off ATT when using the eSIM?
2. And then, for example, when back at the hotel, to use your ATT account, turn off eSIM, turn on ATT, and then send/receive iMessages, FaceTime, phones all over WiFi?

@SuperTuscan 

1.  You do not have to turn off the AT&T SIM you just have to insure that you have the appropriate settings for each SIM. I turned it off just to be sure I did not incur any accidental charges. 

2. You do not need to turn off your eSIM. I turned off my Italian SIM and turned on my AT&T eSIM to make Wi-Fi calls. 

I turned on and off the appropriate SIM/eSIM as needed. This way I knew which SIM was active. 

Thanks @Fl_retire, Im getting confused. You have an ATT eSIM for Italy?  I did not think they made one. Do you mean you turned on/activated your italian eSIM and turned off your ATT SIM (assuming your a US citizen with an ATT account - ATT is not available in Italy; TIM, Vodafone, Wind Tre is).  Please clarify.

Thanks

and then send/receive iMessages, FaceTime, phones all over WiFi?

@SuperTuscan You do not need your ATT sim active or any sim active to do iMessage or FaceTime over WiFi. You only need your ATT sim active to do WiFi calling via AT&T wifi.

@sandblaster , that's correct and maybe I stated it incorrectly. This stuff can get confusing. :). To call from the hotel's wifi ATT needs to be activated.  What if you have an eSIM and you're at the hotel and want to use the hotels Wifi? What steps need to be taken?  I want to send pics via iMessage, use internet. 

What if you have an eSIM and you're at the hotel and want to use the hotels Wifi? What steps need to be taken?  I want to send pics via iMessage, use internet.

You don’t need the esim to use the hotel WiFi. Connect to the hotel WiFi as you would any WiFi. Your choice as to whether you leave the esim active or not. If you want to avoid using cellular via the esim, you can either deactivate the esim or put the phone in airplane mode and turn WiFi back on.