Airalo USA carrier is now T-Mobile per their website. I tested their service when it was first available and on AT&T. It worked great then, but I'm on T-Mobile now as my native carrier. I liked the option for another carrier, especially since Xfinity screwed up the Mobile plans by charging a $12 minimum and forcing migration for those on older "No Data Fee" plans.

Same here, I used Xfinity as my second option (T-Mobile is main carrier on the eSIM). I went back to Red Pocket mobile (CDMA SIM on Verizon) for $5/month ($60 annual plan on eBay) - 500Mb/month, more than enough as a secondary service.

BTW, if you enable Automatic Data Switching in iOS 13, I've read several reports that when there is no service on your main T-Mobile line, it will automatically enable T-Mo WiFi Calling using data on the second SIM; this can be pretty handy :)

I've considered the Ebay Red Pocket option, but quite frankly I get very good coverage and speeds here in Portland, OR on T-Mobile. I realize it's only $5 a month, but when I had the Xfi Mobile plan I only made a few calls a month and had two lines for less than $4 a month total. I was pretty suspicious of the low rate, but I ported in a number for a $100 gift card, so I'm still about $80 up on the whole deal. The port in number came from a free sim on a $3 a month T-Mobile prepaid plan, so that was pretty easy to part with. I might get the Red Pocket service if I ever take any extended road trips where T-Mobile is likely to be spotty, but who knows, maybe 5G will be in place by then?

My current project is trying to get the most out of a 3 UK 12Gb travel sim from Amazon. It really has some interesting possibilities. Especially with the iOS 13 simulated WiFi service.

I'm using a second SIM only because I can; like you, the T-Mobile coverage in my area is on par with both AT&T and Verizon (perhaps just a touch less, but all 3 have various dead spots here).

If a couple of other phones in my family have a need for secondary coverage, I might go back to Xfinity's $12/gig for the month; that's actually not bad spread out over 2-4 lines that won't typically use anywhere near the 1Gb, but do have the option if there's ever a need.

What does the 3 UK SIM get you in the US? Isn't it only valid for 30 days?

The most common version 3 sim I see is the 12Gb, 30 day, $20 edition. I"m looking at it for international travel primarily. You can also get a 10Gb, 30 day, $15 for the 3 network, and near as I can tell it has the same features and roaming coverage. For me, the US usage would only be for confirmation of activation and functionality prior to a roaming trip. My intended use would be for two or more phones with included local and phone to phone calls in the covered areas. With the IMS dual (esim, 3 sim) sim setup we can hopefully keep our phones active for no fee calling to and from the US while abroad without needing WiFi connectivity.

Red Pocket is still the best backup service, but I just don't need it, and the +/- $15 a month new rates from Xfi Mobile aren't worth it to me.

I wonder if this will work as intended, with T-Mobile's International data roaming? Perhaps just turning off data roaming on the T-Mobile line should be sufficient, but I'm curious if it'll connect to IMS using the second line's data when it has a connection to its own service? Do update this thread once you've had a chance to try it out.

I have tried it using 2 T-Mobile lines and it works fine in the US. My primary voice line is on esim and a spare TM voice sim as data service in sim slot allows for dialing with either number. My main objective is to obtain low price data roaming that also has foreign calling included. The IMS free USA calling will be a bonus if it works, and I expect will. I don't know about what quirks it may have though. I'd love to have 10-12 Gb of data for 30 days with included call roaming and 24/7 free USA calling too. Technically it looks promising and I don't see any reason the US calling won't work. Especially with the data provided by a different, faster carrier service than the 256kbps I get from my Promo Plus.

Thing is, T-Mobile won't use the second SIM for data if it has service on its own line - that is a benefit only for No Service areas. So if you just set the phone to use the T-Mobile line for voice and the second SIM for data while traveling, I don't know that T-Mo WiFi Calling will work as you want.

That's true, however I can manually select a carrier with no service (Not TOO hard to find overseas, LOL) for my primary voice line since I have voice roaming, and then it should default to the "Mobile Using Cellular Data" and connect to the sim card line data for calls. That is how it works here and I don't know why it would be any different in other countries. I do not know why that process simulates a WiFi call, but it does. I think I read somewhere that Apple purposely configured it to behave that way in iOS 13.X and above.

CatJo,

You got me thinking about this too much and I ordered a Red Pocket sim on Ebay for $60, 500Mb, 100 min. 100 text per month, 1 year service. A factor in this was the international calling that's included that I was not aware of prior to our discussion. Not a bad deal with a lot of EU countries inc. in the 70 Claimed. As I recall, about half of those are to landline only, the rest include cell & landline. Hopefully it will be useful for arranging hotels & shuttle scheduling prior to US departures. In the mean time I'll have the VZ second line for play in my iPhone 11.

LOL, nice! That Red Pocket is a good deal for a backup line of service.I agree with your assessment of just selecting a network that T-Mobile doesn't support to get it to use the second SIM's data; I just experimented with this last night. So it'll work great while traveling internationally, if one wants (I'm typically happy with the 256kbps service, and have paid for a week of the higher speed service when needed)

Here's a copy of a post I made on MacRumors regarding the esim/WiFi simulation. BTW, calls made this way register on my account log as "WiFi Call" just like one actually made over WiFi.

I've got a new question that occurs to me. If I am roaming overseas and have my iPhone set to the simulated Wifi service over a data line, will I be able to call another iPhone set the same way that is also roaming internationally? Both phones have US numbers and the same configuration. Phone one would dial phone two's US number with a +1 prefix. Would both phones connect using the simulated WiFi connection for no charges? It seems like it should work.

I'm hoping someone will be able to try and make a round trip call using the IMS configuration so I don't have to wait until March to test it.

Here in Spain Airalo really sucks, I've been trying to use it for the past couple of days and it's consistently been incredibly slow despite strong signal. For example, sending pictures using Signal messenger takes over 10 minutes.

Not impressed, hopefully their service works better in other countries.

Which kind of Airalo-sold eSIM did you buy?

The Airalo eSIMs don’t all work the same and the service varies based on which specific type of eSIM you purchased and are using.

GUwonder,

Maybe you could expand on that a little bit.

I know Airalo has their own brand of single country and region sims as well as 7 & 30 day versions of each of those. In addition they market a variation of the "Sim4Crew" service that is data only. Do you have details about variations in service by country, region or duration of service? I'm going to Spain in March and would be interested in hearing more about what you've experienced from their plans. The Airalo website claims they use Vodaphone service in Spain, for instance. I thought they had pretty good coverage there.