eSIM for the USA From the UK: A Practical Guide
Travelling from the UK to the USA? How a US eSIM compares with roaming, how much data to buy, what plans cost, and how to install it before you fly.
An eSIM for the USA from the UK gives you US mobile data on your own phone, without a physical SIM card and without your home network's roaming rates. You buy it before you leave, install it at home, and switch it on when you land. Here is how it works, what it costs and how to choose the right plan.
Do I need an eSIM for the USA, or can I just roam?
You can roam, but check your network's US prices first. Roaming charges vary by network, and Ofcom, the UK regulator, advises you to "speak to your provider before you leave the UK".
A travel eSIM is a prepaid alternative. You pay a fixed price for a set amount of data, and you see that price before you pay.
Will a US eSIM work on my UK phone?
It will if your phone supports eSIM and is unlocked. iPhone XS, XS Max, XR and later support eSIM; for Android, check your exact model.
If you are not sure, read how to check if your phone is eSIM compatible. Phones bought on a UK contract may be locked to that network.
How much data do I need for a US trip?
For a one-to-two-week holiday with maps, messaging and social media, 3–5 GB is usually enough. If you stream video or work remotely, choose 10 GB or more.
Video uses data quickly. Netflix says high-definition video uses up to 3 GB per hour. Our guide to how much mobile data you need when travelling has more examples.
How much does a USA eSIM cost?
Simnetic's US plans start at $0.99 for a one-day pass. The prices below were checked on 15 October 2026 and can change; the USA eSIM page shows current prices.
Data | Validity | Price (USD) |
|---|---|---|
1 GB | 7 days | $1.99 |
3 GB | 15 days | $4.49 |
5 GB | 30 days | $6.99 |
10 GB | 30 days | $12.49 |
20 GB | 30 days | $21.99 |
Day passes marked "unlimited" include a daily allowance at full speed, after which speed is reduced under a fair-use policy. Check each plan's details for its daily allowance before you buy.
Simnetic tip: Each US plan lists its data, validity and network speed (such as 4G or 5G), so compare these before choosing between a day pass and a fixed data plan.
When should I install my US eSIM?
Install it at home on Wi-Fi, a day or two before you fly. Apple notes that your iPhone must be connected to Wi-Fi or a hotspot to set up eSIM in most cases, which is easy at home and harder at the airport.
Check your plan's activation policy first, which each plan shows before you buy. Some plans start when you first use them and others when you install them, so install the second kind closer to departure.
Can I keep my UK number in the USA?
Yes. Keep your UK SIM switched on for calls and texts, and set the US eSIM as your mobile data line. Apple says an iPhone with a SIM tray can use a physical SIM and an eSIM while travelling.
Turn off data roaming on your UK line so it cannot use data abroad. Our guide to keeping your number with a travel eSIM explains the settings.
Does a US eSIM give me a US phone number?
Simnetic's US data-only plans have no phone number. If you need a US number, for example for US contacts, see how to get a US phone number from abroad.
Ready for your trip? Choose a USA eSIM plan.
About the author: Written by the Simnetic team at Domaxit LTD, a London-based provider of prepaid travel eSIM data plans for 217 countries and virtual phone numbers. We check every price and plan detail in our articles against the live Simnetic catalogue before publishing.