So, when Google Fiworks it's great. Sure, it's expensive, but you're paying for simplicity and flexibility. You step off the plane in some foreign country, and it just works. To reiterate: It. Just. Works.

I run dual T-Mobile/Google Fi lines for this reason. With Fi, I get a real/fixed phone number; I get free/unlimited texting; I get full-speed LTE (practically speaking) anywhere in the world; there are no hard data caps or funky billing; and one last bonus: since I've got the SIM card in my iPhone, the Fi number is also iMessage enabled. You can also add (free) data-only SIMs. I stuck one in my iPad and I can walk into any coffee shop, sit down, and I'm immediately productive.

I don't want to have to fiddle around with local SIM cards, or buying eSIMs and prepaying, wondering whether I'm close to reaching my data cap is or whether I'll be throttled. It's a premium for convenience, but it's certainly one I'm willing to pay (to be fair, my job entails supporting services measured in number of nines).

That being said, I've read the customer service if/when you need to call somebody can be atrocious (usually regarding getting a physical phone shipped to you), but generally the actual cell service is simple enough that you'll never need to call someone. I've never had to anyway.

Edit: as draver noted above, you can use the IMS feature to make international calls over data, so with two different carriers, you can force the primary line to use WiFi Calling over the data plan from the secondary line. In practice, this means I can make free international phone calls with my T-Mobile number using the Google Fi unlimited international data plan. On an iPhone, you'll know this works when you see the carrier suffixed with "using Cellular Data" but it does require you to carry two phone plans (which can be prohibitively expensive).

Polytonic,

your summary of IMS should help others expand their options by using this feature. It does work well in the US for trials, so I encourage those with the necessary gear to experiment with it. I address the second line data by using either an esim data service, or just one of the 4 free lines T-Mobile has given me over the past few years. At 256kbps there is plenty of bandwidth for calling. On iPhones with esim since 2018, you can assign a carrier to lines individually, so that streamlines the setup. The beauty of this setup is you can change your data carrier at will, depending if you only want active, free US cellular calling, or need to switch to a higher speed paid data plan for your second line. I have my primary voice line on esim, my secondary T-Mobile free line on esim, and frequently an Airalo esim also. Any 2 of the 3 can be active on an iPhone 13 Pro Max. My sim slot is also still available for a foreign roaming sim, like "3" Hong Kong, depending upon my needs.

I can provide a detailed setup checklist for IMS if anyone is interested. It is fairly simple, but requires a dual sim, dual service phone. Or, you can just run a hotspot if your home carrier allows for free WiFi calling to the US like T-Mobile does. I have done that using an iPad Mini 5 as hotspot for my travel group with a data sim.

Yeah, Airalo or similar is a good option too (for getting free international calling over data, or if you need a lot of data cheaply). The iPhone 13 added support for Dual eSIM + Physical SIM (so total of three SIMs, one more than XS/11/12 which are limited to eSIM + Physical SIM) so it's pretty easy to test out all the carrier services. You can get a free month of Google Fi from promo code or referral, or give Visible a shot, Mint Mobile, etc.

I thought T-Mo's 256kbps international roaming was pretty good until I ended up in downtown Singapore trying to load Google Maps over Edge (2G) and it's definitely not an experience I'd like to repeat.

On an iPhone it should be pretty straightforward. Depending on version, it should basically be disabling Roaming on the line you want to call from, or possibly Cellular Data on that line if it's being finicky.

No clue about the Android side of things. I think the newer Samsung Galaxy devices are DSDS, but I can't comment definitively on that front.

Were you in Singapore recently?

256kbps is definitely way too slow, and you'll also have to deal with latency as your phone is relaying data back to the US. I wish TMO would make it a minimum of 512kbps. The speed needs to be "usable" by any definition, such as using Google Maps. Having said that, data is relatively cheap in Singapore, so that I would buy a local SIM.

We spent a few days in downtown Singapore a few years back, in 2018 or '19. My experience was like yours, but I have found poor mapping in large cities mostly due to the towering buildings blocking the GPS service to my phone down at street level. It took quite a while to get a fix usually. I was using Apple Maps but just for walking, no vehicle navigation. I use 256k data frequently around the world with my iPad Mini 5 and iPhone, and once the bitmap map loads, it seems to work pretty well. I frequently use a download map app called "Pocket Earth Pro" that has some really nice features, but not so great for driving. It's good for planning and requires no data, with good maps of everywhere I have looked. A nice feature is that it shows trails and footpaths lacking in most maps. Very useful around many tourist spots.

As little as I am overseas, which I'll guess will be one trip four weeks long per year, with little use of voice or text (the capability is primarily an insurance policy), perhaps I should just sign up for Fi and turn it on as needed. I'll still need data, but that's a separate issue.
Wait, are you saying I can have multiple eSIMs (with one active, of course, on an iPhone SE 2nd iteration) and switch between them on the fly? I hadn't understood that. Please confirm, if it's true.
I would appreciate it. Thanks.

Serpens,

This will allow a US carrier with WiFi calling to use that feature to call from an international location (Or In The States Without WiFi) over data. You will need to determine if they may charge for that service.

For iPhones with Dual Sim, Dual Service and either 1 or 2 esims or an esim and a sim card service, Turn OFF WiFi. Turn on Data Roaming on your Data sim when overseas.
Open Settings-Cellular-Your Voice Line-Network Selection. Turn OFF Automatic. Choose another carrier like Sprint or, 313-100, (For Testing In The US) which is the First Responder network. It is important that your voice line not have any roaming carrier service. Overseas it MUST be assigned to another carrier like Vodaphone or "3" UK, etc. This prevents your voice line from having a roaming voice connection with your home carrier.
If you have a sim card from another service, it needs to be active in the phone. Confirm it is getting data by opening a map or stock market app, etc.
Your dual sim iPhone should momentarily display "No Service" for your voice line, then switch to read "Using Cellular Data" in the upper Status Bar display. Your data sim line should also have some signal bars and 3G, LTE, etc. displayed.
That is all that is needed. You can use two esims for the same type of setup. I use a free voice line on a second esim and just leave them both on.

I just wrote this on the fly, so if you have any questions or corrections, just let me know.

Switching between esims is done in: Settings-Cellular-Cellular Plans-ON,OFF. Easy Peasy.

Edited to add you need to have WiFi calling switched on for all of this to work under: Cellular-Cellular Plans-Each Line In Use.

Thank you, draver.

No, this would have been a few years back, pre-COVID, and likely also due in part to incompatible GSM bands at the time, so a local SIM card probably wouldn't have saved me either. Phones are much better these days, thankfully, but 256kbps is still the technical definition of Edge/2G. You could pay T-Mo an arm and a leg to upgrade to the plan with faster international data (ONE+/Magenta+) but then you're paying even more money for 3G speeds at best. Most of the modern/mobile web is designed around everybody having LTE connections all the time, which is ... unfortunate.

For a lot of the stuff I'm doing, websites simply fail to load on 256kbps connections. To the degree that it's not reliable internet for me anymore. Relying solely on GPS for location services is a great way to nuke your battery life too.

Fi billing allows you to freely switch between plans as-needed, so you could maintain a Flexible plan (and basically not use it) for as little as $20+taxes (I pay ~$27/mo. in WA after all taxes and fees) and then switch to Unlimited Plus as-needed (~$65/mo.). Strictly speaking, on a $/GB scale, this is laughably expensive compared to Airalo or similar, but on a value for money scale, it's way up there for me.

Yes, you can have multiple eSIMs on a device at once. For your particular phone model, your hardware permits active cellular connections over one active eSIM and whatever is physically inserted into your nanoSIM tray. With an iPhone 13, you could instead use two concurrent eSIMs. With multiple SIMs loaded, you gain the option to select which data plans to use. I'd post a screenshot, but there's no way to do so easily without giving away my phone numbers. :)

I must have had another misunderstanding. I thought I could turn Fi off, so there was no charge, perhaps for months at a time (and use Google Voice in the interim).
Thanks for clarifying that.

What, you didn't want me to call and thank you?

Fi can be paused for 3 months

https://support.google.com/fi/answer/6079346?hl=en

Thanks for the link. Perhaps I was thinking of changing Google Fi to Google Voice and back again, which is apparently allowed.

and unless they've decided to care enough to stop you from doing it, it can be resumed for 2 minutes and then immediately paused for 3 more months. Each time you do that, you get billed a couple cents.

This also works, but it's an actual number port on the backend, so while it's usually pretty quick sometimes your number goes dead for 2-3 days when switching, so plan ahead if you're planning on doing this.​​​​​​​

as long as the plan is not on the unlimited plan, that may work. Looks like the unlimited bills for the entire month

I got my wife a Pixel 5a after her 3 XL died. Then I got one for me. I use my iPhone when domestic, but use the Pixel when international. The iPhone is my primary number for 2FA etc, but that Pixel 5a just rocks. The best use of it is sharing the hotspot when in a hotel, train, airport lounge or cruise ship. So my google Fi number is on the esim on the 5a, and I have a Tmo in the sim slot. The past 2 weeks we were in Switzerland, and the Fi piece of that just was great. I would switch to the T mo for a bit, but I could not tolerate the slow speed. But if I wanted to save data and just needed maps I would switch to the Tmo data for a bit. I really like the flexibility. If the iPhone would share the wifi through the hotspot, then I would be pure iPhone. But I don't see that happening.