21 day tour - desire connectivity for phone calls to USA

If your timing for making calls coincides with being in your hotels, you could just use FaceTime for video calls for free when you’re connected to the hotel wifi. I use FaceTime almost once a day when I’m in Europe to talk & see my husband back at home.

We use WhattsApp for video chat and text, using the hotel WiFi we have Samsung phones also. We just switched from Verizon to TMobile (what a pain that was) just for the International calling/data benefits they have.

Use WhatsApp.

Be sure who you intend to contact in the US also has it on their phone.

Learned about it a few years ago when the AirBnB host of my London apartment rental had to fly to China to see her parents. She told me about the app which was free so I downloaded it and have used it ever since.

I have an iPhone.

If your phone is unable to work with a "new sim" card, what about getting a cheap phone and using that while you are there? I swapped to GoogleFi once I could for that very reason, works almost everywhere.

Skype, works with wifi, party that you are calling does not need to have Skype.

We’ve been told Signal is similar to WhatsApp but it is encrypted.

Install the Google Voice app on your phone before you leave the US. Then, you can use the app to call any US phone for free, even landlines. (Though you will still need to be on WiFi or mobile data.) The person you are calling does not need Google Voice - obviously you can't install an app on a landline. Google will give you a new, second phone number to use with the app.

Skype works in same way but isn't free for the calls. At worst you can use Skype and buy credit in $10 blocks to be able to make cheap voice calls to US phones. In the past, Google did not allow prepaid phones (which Straight Talk technically is) to use Google Voice like this, but things may have changed since then - not sure. I'd install Google Voice now and try it out. if it works now, it will work in Europe. (For texting too, using the Google Voice app.) But it works with your new Google number, not with your Straight Talk number.

You still need WiFi (or mobile data) to use Facetime, WhatsApp, Skype, etc. If you can get Google Voice to work, that's free for the calls you want so that's how I'd go. I've been using Google Voice for years.

Thanks to Andrew’s advise several years ago, I use Google Voice to call home to landline. Works good unless hotel WiFi is weak. Saves me $10/day Verizon international plan when I don’t need it for anything else.

When I'm connected to wifi with my phone I'm able to call family members via the Messaging (that I use for texting too) app. Doesn't work for landlines, but it does work for cell phones that I also send texts to. Just have to be sure you are on airplane mode and that your Android is set to enable wifi calling. I have a Samsung phone that it works great for and it's been my go-to for calling back to the US especially when it's to someone who doesn't have WhatsApp installed and is easier than trying to use FaceTime on an Android phone. If you're able to connect to wifi at home on your phone, you shoild be able to use wifi calling in Europe as well for free.

WiFi Calling would be a great option if Straight Talk allows its use internationally now. A quick google shows that at one point at least they did not allow WiFi Calling to be used internationally, but that may have changed. I'd still install Google Voice anyway, since it's free, in case WiFi Calling doesn't work out. At worst install Skype so you can call everyone even if not free - just a few cents per minute.

"We’ve been told Signal is similar to WhatsApp but it is encrypted."

WhatsApp also has end-to-end encryption, and is more widely used than the likes of Signal nd Telegram.