Originally Posted by
draver
I've been shadowing the US Mobile Reddit posts recently and it seems they are adding some features we may find useful for travel communication. The main feature I'm most interested in, is the free WiFi calling while roaming internationally. This is different than what my main carrier, T-Mobile graciously provides. According to their staff over chat, their Shared and Unlimited plans offer free WiFi calling WHILE IN a foreign country TO a foreign number.
I've been using US Mobile for about 6 months. Obviously they have a few different plans (and seem to change their plans almost monthly) so the exact details might vary, but...
You're mixing two mostly unrelated concepts here, so lets address them individually. Firstly, Wifi calling. Yes, they support it. Yes, it works (with one catch) over both wifi as well as over a data connection from a second SIM if your phone supports that. I've used this extensively in multiple different countries without issue. The catch I mentioned is that if you're on their Warp 5G (Verizon) network, then you can NOT enable 'Backup Calling' on a Google Pixel device - which means you can't make "Wifi" calls over a separate data SIM. I can't speak for other phones as I haven't tried it, but it does work fine when using the US Mobile "GSM 5G" (T-Mobile) network. (From here on, where I say "Wifi calling" I mean both over Wifi and over a 2nd data SIM)
Wifi calling has nothing to do with your location. It works exactly the same if you're in the US or in Antarctica - in fact for the most part they won't even know where you are. So that covers the "WHILE IN a foreign country" part of your question - it'll work fine.
Which brings us to the "TO a foreign number" part. All of their plans (except the Light and Kosher plans, where it's an extra $2-3/month) include international calls TO a number of countries. This is explicitly listed on their website as being "Int’l calls from US" - but if you're using Wifi calling then for the purposes of this you ARE coming "from the US", so calls to those countries ARE included, and are free - just like they would be if you were physically in the US using Wifi calling.
Put those two concepts together, and yes, you can call using Wifi calling FROM any country, TO any country on their "included countries" list for free. I've used the Wifi calling (both over WiFi and a separate data SIM) part of this from about 8 different countries now, and it's worked fine from all of them. I haven't used it to call a non-US number as I'm on their Light plan that doesn't include that, but I have sent SMS to foreign numbers which uses (basically) the same mechanism and it's worked fine.
Originally Posted by
draver
This is very different to the $.25 a minute T-Mobile charges for calls abroad.
Yes and no. T-Mobile also allow Wifi calling from overseas for free, as (as far as I'm aware) do all US carriers that support Wifi calling. The T-Mobile 25/cents thing you're referring to is for standard roaming - ie, calls going over the mobile network, not over a data network (wifi or from a 2nd SIM). US Mobile do also offer calls over the mobile network, as well as roaming data, but it's not included in their 'sharable' plans and has to be purchased separately ($15/1GB data if I recall, not sure about calls). It IS available in their unlimited plans, but those start at $29/month unless you want to pay annually.
Originally Posted by
draver
They state that 200+ countries are available. Both plans are available on sim cards or esim. I could not find a comprehensive list of countries included, however a search page is posted.
https://www.usmobile.com/international-calling
Originally Posted by
draver
The Shared "Warp 5G" plan @$10 a month includes 2Gb data, unlimited talk & text on either Verizon or T-Mobile in the US.
That's not quite correct. The "Warp 5G" plan is Verizon only. The "GSM 5G" plan is T-Mobile only. ie, whilst US Mobile supports both networks, you pick which one you want to be on - you don't get both at once. You can change between them, but it involved an "internal port" and you lose the rest of your current months service and have to pay for a new month on the new carrier.
Originally Posted by
draver
My postings have never been on or about T-Mobile WiFi calling, so I apologize if they seemed to be. They are one of the carriers the MVNO US Mobile and its’ plans that are based on, along with Verizon service. Those plans are called “Warp 5G”. Currently they offer 3 Warp plans that utilize the VZ US carrier that have foreign roaming. They are called “Unlimited Starter, Unlimited Premium, and Shared Data”.
The Warp 5G plans do NOT currently have roaming data/calls. That feature is "coming soon". Only the "GSM 5G" (T-Mobile) plans have that today.
Originally Posted by
draver
Roaming data is data, it doesn’t matter if it’s Airalo or T-Mobile. It is only the medium within which IMS functions. You probably didn’t mention how their roaming data was being used to your friend, or they are ignorant of it’s capabilities also.
Yes and no. The problem is that no phones (that I'm aware of) allow you to make a "Wifi" call over the data channel of the same SIM. ie, If you're overseas and you have (only) a roaming T-Mobile SIM, and you make a call, it's going to make a roaming call over the "voice" network. (Technically this gets confusing because it'll actually be a VoLTE call, so technically it's over the data network as that's what all 4G calls are, but just lets ignore that for a moment). Thus T-Mobile will charge this as a voice call, and you'll get hit with roaming charges for it. If you've 2 SIMs (say T-Mobile and Airalo), and if your phone supports it, then you can tell the phone to route the T-Mobile call over the Airalo data connection, and T-Mobile sees it as a Wifi call - and it's free.