esim question about activation upon arrival in the UK

Many of your questions will be answered when you purchase and download one to your phone, the reliable companies have very good tutorials that take you step by step, typically dedicated instructions for your brand of phone.

You don't need to have data service to activate it once you land, because on your phone you are going to go to where your networks are found and switch your phone settings from your phone using your current sim card to the esim which will then fire up and roam on it's chosen networks (make sure you have roaming activated on your phone). It's the same as putting a physical sim card in your phone switching out your existing one except there is nothing physical to switch, you do it with menus on your phone and don't need to remove your current sim card from the phone.

One thing to know is many esim carriers don't offer a phone number with your esim so you won't get phone calls or texts to your phone number. Some offer a phone number some don't. But it depends how much you need a phone number to give people. (remember this won't be your current phone number)

I have t-mobile so I just set my settings to data for the esim and text and phone calls to my physical sim since I get free international texts with tmobile. You''ll see in your menus you can mix and match what uses what.

Also understand in most of Europe, Africa, South America you'll be communicating with people via What's App which is what everyone will be using so your usual text service isn't really necessary.

"most of Europe, Africa, South America you'll be communicating with people via What's App'

That varies significantly depending on country and age demographic - a local number can be handy if you need to phone your hotel. I do use WhatsApp quite a lot in the UK, but I would say it's more of a standard phone call market than, for example, here in Singapore where literally everyone uses WhatsApp.

the Orange eSIM app for travelers has great instructions, which basically reduce to this -- distinguish between 'installing' and 'activating'. You install the eSIM when you buy or at least before you leave home by using the QR code or the passcode that they provide to you -- you put that eSIM info into one of the virtual slots in your phone, where your usual eSIM is the primary. [on the new iPhones there are at least 8 slots available, and if you want to customise the names you can]
You activate the new eSIM most simply by putting your phone in airplane mode while on the airplane (as the crew asks you to do) and while in airplane mode you switch your data provider, and maybe your voice and text provider depending on the plan, to the one you bought. Sometimes you just need to switch off your primary provider and it will automagically use your other / newer one; sometimes you need to deliberately turn on the new one-- 'activate' it.
When you get off the plane and turn off airplane mode, the phone will update the time and location through the airport's wifi and you will also likely get a notification on your phone that you're using the other provider, and you might also get a message or email from them welcoming you. Ta-da!

A few things that you should to do ahead (for all 5 phones): 1) verify they're unlocked by Verizon (if locked you can't add any kind of SIM card); 2) verify all phones accept eSIMs (not all of them do); 3) if you're not using iPhones that use a data based iMessage service, before you leave make sure everyone in your family has downloaded and knows how to use a different communication tool (like WhatsApp); and 4) make sure everyone knows the steps to deactivate the Verizon SIM cards before you arrive (see instructions already provided above) - just one ping to a cell tower triggers the international charge.

Already noted but bears repeating: you will not be using your US/Verizon phone numbers while using an eSIM. If it is important for any of your family members to communicate using their stateside number, then you will need to use the Verizon international option. If you have teens in your numbers, that could be a meaningful issue.

Have a great trip!

"just one ping to a cell tower triggers the international charge.'
Is this a carrier-specific issue? We only pay roaming charges if we make or answer a call, or send a text - there's no charge to roam per se. So I usually leave my normal SIM on even when I have another SIM in the phone, just in case it's an important call.

Simon it was true for my phone a couple trips back but it may not be universally true, thanks for pointing that out. So many phones have apps that run in the background, it is simply safer to make sure the SIM card you don't want to use is turned off before you land.

Like T-Mobile, Google Fi doesn't charge for international texts. I have no idea what Verizon's policy is. I can continue to use my native telephone number to send and receive texts at no charge, even after activating an eSIM. That's actually the trickiest part of the process for me with a Samsung phone. I have to do some fiddling to get the phone to use my Fi eSIM for outbound texts; it seems to need that direction for each recipient rather than providing a single setting I can use. If I don't make that change, my outbound texts go nowhere, because there's no telephone number provided with a data-only eSIM.

Troubleshooting tips:

The eSIMs I've purchased from Airalo have come with good instructions, but the connection to the local phone provider isn't necessarily instantaneous. I assume there's an electronic handshake going on in the background that can take a few minutes on occasion. If you don't have cellular-data access within a few minutes of arrival in the new country and turning on your eSIM, first review the instructions provided by the eSIM provider to be sure you haven't skipped a step. Next, check to be sure roaming is turned on; I think I've had to do that manually for each eSIM. If still no joy, it won't hurt to reboot the telephone, though that's not usually required. That has seemed to help me on occasion, but those successes may have been purely coincidental.

I travel a lot in Europe, and I've learned not to freak out if I temporarily find myself without a data connection; I assume that's indicative of an issue with the local network I'm connecting to. That happened to me--usually briefly--when I was using T-Mobile, and it happens from time to time with Google Fi as well as occasionally when I'm using an eSIM.

Remember that there may be dead zones in rural areas, just as there are in the US.

Regarding "Time to connect", I have Tmobile, and it's pretty instantaneous when I arrive in another country, probably because Tmobile is Telecom, which is a native carrier in Germany. Conversely, I have a "Three" sim (Great Britain) in a backup phone. It will "roam" in the USA (at high prices), but when I turn the backup phone on in Michigan, it literally takes 10 minutes before I get a "welcome to the USA" text.

Also, most carriers and most all newer phones support "wifi calling". It needs to be turned on to work. It allows me to get wifi from a hotspot and text or call using my "normal" phone number. You will all probably want to do that, as nobody wants to try texting their friends at home from a British phone number. And most of their friends will not be able to quickly add a +44 to the phone number in their contacts list to call you. One possible problem with "wifi calling" is that possibly Verizon will consider this "roaming" and charge you. Others will know more about that.

But if everyone is ok with texting friends with Whatsapp or Google Voice, or whatever, then all you need is data, and a data-only esim will be simpler and cheaper than one that comes with a phone number.

Data only calling, as with eSims, may only allow calling to cell phones or anything that gets WhatsApp, Messenger et al. You should check this with the provider, as to whether you could ever call a hotel that might not have WhatsApp, for example. I got caught with this on my last trip to the UK, because my Sim Card (though Three) would only do data calls, and I couldn't call a shop I had reserved something to buy. It was rather frustrating at the time, because I didn't know what was going on. I just couldn't connect; then I called Three and they confirmed "data only".

Regarding WiFi calling, it has been my understanding from my provider, that one type only works when connected to a wired wifi network. I tried it when connected to Heathrow's network but it didn't work for calling Canada. So I am not sure at all how practical it is using your own US number, and again (!) my provider could not tell me what was going on when I got home and asked them. But wifi calling using data like Messenger or WhatsApp is different; that works on your sim data card. So there are 2 types of wifi calling: one where you just use your own North American number, and you can call within the country you are in, or to NA, and the other is using data calling with Messenger, WhatsApp and those.

Maybe somebody can enlighten us?

Good info, phoffen2001, thanks. It got me thinking. There is some confusion about what is "wifi calling". Simplified, there are 3 ways to send a text or voice call:

1. Using Internet Data (not wifi-calling): This is using Messenger, Whatsapp, Google Voice, TextNow, etc... In these, you have your app on your phone or laptop communicating through the internet (either cellphone data or wifi data). You are identified by a username, or a phone number assigned to the app provider you are using. Not identified by your "normal" cellphone number. You may be paying your cellphone carrier for cellphone data you are using, depending on your plan. This probably works internationally with no problems, but your grandmother sees a phone number she does not recognize.

2. Using the cellphone network: In this case you are communication through the voice or text protocols of the cellphone network. You are identified by your "normal" cellphone number. You are paying your cellphone carrier, for each domestic or international call or text, depending on your plan. International roaming (when you are in another country), may be very expensive, and may or may not work, depending on your carrier. You need to read the terms of your plan.

3. Wifi Calling: This one is more complicated. It means your cellphone carrier is very involved. You are identified by your "normal" cellphone number. If your carrier plan does not offer wifi calling (some do not), you won't be allowed to select "wifi calling" on your phone. If you are allowed, your phone will have the option of using wifi to make the call to get better voice quality. The carrier then has to encode your voice or text into data, send it over the internet to some other provider or app, and make the connection. Your carrier may very well charge your for that, as they have to pay the other provider to complete the connection. These charges can add up to a lot of money if it's an international call.

Notes:

1. Roaming means calling outside of your home country, except many USA or Canada carriers offer plans which include Canada, USA, and Mexico as being "domestic" calls. The EU is moving to including the EU countries as one area for roaming purposed (but Great Britain is not included).

2. Some networks, particularly Great Britain and maybe EU, distinguish between calls to other cellphones and calls to landline phones. They may charge more for calling landlines, or they may just not do it. That's because they have to pay more, and do more work, to make a connection to a bunch of copper wire owned by other companies. Again, you need to read the terms from your cellphone plan.

3. As has been mentioned on this forum, simply enabling "wifi calling" on your phone does not mean that the cellphone network is not being used. It is used by your carrier, and the receiving carrier, and folks have mentioned getting huge bills from Verizon when they thought "wifi calling" would always be free. I think it is free for Tmobile, and not sure about AT&T.

I hope this is all correct, please correct me if I'm not.

Excellent! Thanks for that very useful breakdown.

One more thing I have experienced: When wifi calling is enabled on my phone at home, my phone will cut out after a while. I think it is is because it tries to switch between the wifi calling using the wifi network in the house, and the cell data from the phone (the one you use when out and about). I have to turn off wifi calling in the house if I want to make a call. Again, my provider doesn't know why. Apparently they don't know much. But they do know how to sell you a plan. How this affects travellers is that when in a hotel, and one wants to use their wifi, it works as it does in my house. If the phone is using cell data, it works as if one was outside, or wherever. I personally have never had an issue with the switching between the two, when travelling, but again, not exactly sure why!

Last year, I signed up at GiffGaff to have an esim mailed to me. When I got to England, I activated it in my unlocked phone. I paid ten pounds sterling for 15GB which was more than enough for 10 days. I was very worried about doing this but it went quite smoothly!