The safest way to avoid roaming fees in the US is to switch Data Roaming OFF on your home line and run a dedicated US data eSIM instead, starting at £2.59 for 1GB/7 days. Your home SIM stays active for calls and texts, but it never touches the American networks at your network's expensive roaming rate. Your data rides on the eSIM at a flat, prepaid price you set before you leave. This guide walks through every tap on iPhone, adds the Android equivalent, and explains why one wrong setting can cost more than your flights.
The whole setup takes about three minutes and you can do it at home before you fly. Let's start with why this matters.
Why "Accidental Roaming" Costs So Much
Bill shock in the US almost never comes from a decision. It comes from a default. Your phone lands, sees no home network, and quietly latches onto AT&T or T-Mobile at your network's international roaming rate. You never chose it. You just turned your phone off airplane mode to check a map.
For a traveller from Europe, the UK, Australia, or Canada, US roaming is one of the most expensive corridors in the world. Many networks charge a daily "roaming pass" of $10-15, and off-pass rates can be brutal per megabyte. A single automatic photo backup or an app updating in the background can burn through your allowance while your phone sits in your pocket.
The fix is not to be careful. Being careful fails the moment you are jet-lagged and want directions to your hotel. The fix is to make roaming impossible on your home line and put all your data on a separate eSIM you control. Then there is nothing to forget.
US eSIM Plans and Pricing
| Data | Duration | Price |
|---|---|---|
| 3GB Data | 15 Days | £3.60 |
| 5GB Data | 30 Days | £5.39 |
| 10GB Data | 30 Days | £9.71 |
| 20GB Data | 30 Days | £17.47 |
| 50GB Data | 30 Days | £39.32 |
| 1 Day | 1 Day | £2.59 |
| 2 Days | 2 Days | £5.19 |
| 3 Days | 3 Days | £7.78 |
| 4 Days | 4 Days | £10.20 |
| 5 Days | 5 Days | £12.93 |
| 6 Days | 6 Days | £15.67 |
| 7 Days | 7 Days | £18.41 |
| 8 Days | 8 Days | £19.78 |
| 9 Days | 9 Days | £21.83 |
| 10 Days | 10 Days | £23.20 |
| 11 Days | 11 Days | £25.25 |
| 12 Days | 12 Days | £27.30 |
| 13 Days | 13 Days | £28.67 |
| 14 Days | 14 Days | £30.04 |
| 15 Days | 15 Days | £32.09 |
| 16 Days | 16 Days | £33.46 |
| 17 Days | 17 Days | £34.15 |
| 18 Days | 18 Days | £35.51 |
| 19 Days | 19 Days | £37.57 |
| 20 Days | 20 Days | £38.94 |
| 21 Days | 21 Days | £40.30 |
| 22 Days | 22 Days | £40.99 |
| 23 Days | 23 Days | £41.67 |
| 24 Days | 24 Days | £42.36 |
| 25 Days | 25 Days | £43.04 |
| 26 Days | 26 Days | £43.73 |
| 27 Days | 27 Days | £44.41 |
| 28 Days | 28 Days | £45.09 |
| 29 Days | 29 Days | £45.78 |
| 30 Days | 30 Days | £47.15 |
Every plan is prepaid and data-only, delivered as a QR code by email the moment you buy. There is no activation fee, no contract, and no US phone number to manage. You pick the data amount, install it, and you know your total cost before you ever leave home. The US eSIM connects to a major US network such as T-Mobile or AT&T, so you get real 4G/5G coverage in cities and along the interstates.
Step 1: Turn Off Data Roaming on Your Home Line (iPhone)
Do this first, before you even install the eSIM. On modern iPhones each SIM has its own roaming switch, so you are turning it off for your home number specifically.
- Open Settings and tap Mobile Service (called Mobile Data or Mobile Service in some regions).
- Under SIMs, tap your home line - the one from your normal network.
- Scroll to Data Roaming and switch it OFF.
- Optional but recommended: on that same home line, set Turn On This Line to on for calls and texts, but you will hand data duties to the eSIM in a later step.
That single toggle is the one that saves you money. With Data Roaming off on the home line, your iPhone physically cannot pull mobile data through your home network while abroad, so the accidental-roaming trap is closed. Calls and SMS still work if you leave the line switched on, which is exactly what you want for two-factor codes and keeping your own number reachable.
Step 2: Install Your US eSIM
If you bought your eSIM already, you have a QR code in your inbox. Install it while you still have Wi-Fi at home - installation needs internet, but activation later does not.
- Open Settings > Mobile Service > Add eSIM (or Add Data Plan).
- Choose Use QR Code and scan the code from your confirmation email.
- When prompted, give the eSIM a clear label like "USA Data" so you never confuse it with your home line.
- Decline any prompt that offers to make it your default voice or iMessage line - this is a data eSIM, and you want your home number to keep handling calls and messages.
If scanning is awkward, most providers also give a manual "Enter Details Manually" option with an activation code. Our full walkthrough with screenshots lives on the eSIM installation and activation page.
Steps 3 and 4: Roaming ON for the eSIM, Set It as Your Data Line
The last two toggles are the generic travel-eSIM mechanics, so here is the short version. On the eSIM line (Settings > Mobile Service > USA Data), turn Data Roaming ON - a travel eSIM "roams" onto its US host network, so it needs that switch even though the plan is prepaid and costs nothing extra. Then, under Settings > Mobile Service > Mobile Data, select the USA Data eSIM as your data line, and turn OFF "Allow Mobile Data Switching" so the phone can never fall back to your home line for data.
That is the split you want: home line with roaming off (safe), eSIM line with roaming on and carrying all data. For the full explainer on this setting, see Data roaming on or off for a travel eSIM.
The Android Version (Samsung and Pixel)
Android wording varies by manufacturer, but the logic is identical: Data roaming OFF on the home SIM, Data roaming ON on the eSIM, and the eSIM set as the Mobile data SIM. On Samsung the controls sit under Settings > Connections > SIM manager; on Pixel under Settings > Network & internet > SIMs. Samsung Galaxy S20 and newer and Pixel 3 and newer all support eSIM. For a device-specific guide, see eSIM for Android; iPhone users can check eSIM for iPhone.
Why a Dedicated Data eSIM Beats "Just Being Careful"
You could try to survive on airplane mode plus café Wi-Fi, toggling data on and off. It works until it doesn't - the one time you forget, the roaming meter runs. A dedicated data eSIM removes the human error entirely:
- Your cost is fixed in advance. You paid a flat prepaid price. There is no surprise bill, because your home network is not in the loop for data at all.
- Your home number stays live. Calls, SMS, and two-factor codes keep arriving on your real number over the still-active home line. Apps like WhatsApp stay tied to that number too - see how to keep your WhatsApp number on a US eSIM.
- Nothing to remember day to day. Once the four steps are done, you just use your phone normally. The wrong network is simply not reachable for data.
If you want to weigh this against a network roaming pass directly, our eSIM vs roaming comparison lays out the real trade-offs. And if you are still choosing a plan, the best eSIM for USA guide covers coverage and data sizing for common trips.
How Much Data Should You Buy?
Maps, messaging, and light browsing are frugal. Streaming video and hotspotting a laptop are not. A rough guide for a week in the US:
- Light (maps, WhatsApp, email, occasional browsing): 1-3 GB
- Moderate (social media, some music streaming, photo uploads): 5-10 GB
- Heavy (video calls home, streaming, laptop tethering): unlimited or a large bundle
Get a personalised estimate:
Frequently Asked Questions
If I turn off Data Roaming, will I still get calls and texts?
Yes, as long as you leave the home line itself switched on. Turning off Data Roaming only blocks mobile data on that line; voice calls and SMS still come through on your normal number. Be aware your home network may charge for calls or texts received while abroad, so use WhatsApp or iMessage over the eSIM's data for cheap communication.
Why does the eSIM need Data Roaming turned ON if roaming is the thing I'm avoiding?
Because a travel eSIM does not have its own home network in the US - it "roams" onto a partner network like T-Mobile or AT&T. That is normal and already priced into your flat plan, so there is no extra charge. The roaming you are avoiding is your home network's expensive rate, which the switched-off home line takes care of.
What is "Allow Mobile Data Switching" and should I turn it off?
It is an iPhone feature that lets the phone temporarily use your other line for data if the active one has weak signal. Convenient at home, dangerous abroad - if it switches to your home line, you are roaming at full rate. Turn it off so data only ever comes from your US eSIM.
Can I set this all up before I fly?
Yes, and you should. Install the eSIM over home Wi-Fi and configure all the toggles in advance. The eSIM simply activates when it finds a US network after you land. Installation needs internet; activation just needs signal.
Will this work on my phone?
Any iPhone XR or newer, Samsung Galaxy S20 or newer, or Google Pixel 3 or newer supports eSIM and this dual-line setup. Your phone must be network-unlocked. Check the full list on eSIM compatible devices.
Do I need to change anything back when I get home?
Just two taps. Set your Mobile Data line back to your home SIM, and you can delete or keep the US eSIM for next time. Leaving Data Roaming off on your home line is a good permanent habit anyway.
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