USA Travel SIM from the UK: eSIM vs Roaming vs a US SIM

For a trip to the USA from the UK you have three options: roaming with your UK network, buying a US SIM when you land, or using a travel eSIM bought online before you fly. A travel eSIM is data only, so you keep your UK SIM in the phone for calls, texts and bank codes.

Your three options

You can stay on your UK network with roaming, buy a US prepaid SIM when you arrive, or install a travel eSIM before you fly. Each works differently for data, calls and your UK number, so the right choice depends on how long you are going, how much data you use and whether you need to keep your UK number active for calls, texts and bank codes.

Roaming keeps your normal SIM and number working, but UK networks charge for using data in the USA, so check your own network's roaming price before you travel. A US prepaid SIM gives you a US number and local data, but it needs a shop visit or delivery. A travel eSIM is bought online before you fly and delivered by email as a QR code, and it is data only.

Whichever you pick, your phone must be unlocked and eSIM compatible if you plan to use an eSIM. If you are unsure, check your phone supports eSIM before you buy anything.

Roaming with your UK network

Roaming means using your existing UK SIM and number in the USA. It is the simplest option because there is nothing new to install, but UK networks charge for using data in the USA, so check your own network's roaming price before you travel. If the price is high, a travel eSIM or a US SIM can work out better for data.

With roaming you keep your UK number for calls, texts and bank codes, and you do not need to change any settings beyond making sure data roaming is switched on. The catch is cost: UK networks charge for using data in the USA, and the price varies by network and plan. Check your own network's roaming price before you travel so you know what a day or a trip will cost.

If you decide to roam, make sure data roaming is enabled on your phone. On iPhone you can turn roaming on or off on iPhone in Settings. If you would rather not pay roaming rates for data, you can keep your UK SIM for calls and texts and use a travel eSIM for data instead.

Buying a US SIM when you land

A US prepaid SIM gives you a US number and local data, but it needs a shop visit or delivery. You buy it from a US carrier or retailer, either in a store after you land or by ordering it to an address. It is a physical SIM, so your phone must have a free SIM slot or you replace your UK SIM.

A US prepaid SIM can suit longer stays or trips where you want a US number for local calls. The trade-offs are time and setup: you need to find a shop or arrange delivery, and you may need to provide ID. If you replace your UK SIM, you lose access to your UK number for calls, texts and bank codes unless you keep it in a second phone or use an eSIM alongside it.

If your phone is eSIM compatible, you can keep your UK SIM in the phone and add a travel eSIM for data, which avoids a shop visit entirely. If you are not sure whether your phone supports eSIM, check before you travel.

Using a travel eSIM

A travel eSIM is bought online before you fly and delivered by email as a QR code. It is data only, so you keep your UK SIM in the phone for calls, texts and bank codes. Your phone must be unlocked and eSIM compatible, and you install the eSIM before you travel so it is ready when you land.

A travel eSIM is data only, which means it does not give you a phone number for calls or texts. That is usually fine because you keep your UK SIM in the phone for calls, texts and bank codes. Your UK SIM stays active for those, while the eSIM handles data.

To set up a travel eSIM:

1. Check your phone is unlocked and eSIM compatible.
2. Buy a plan online before you fly. For the USA, see USA eSIM plans.
3. Install the eSIM by scanning the QR code from your email.
4. When you land, turn on the eSIM line and set it as your data line.
5. Keep your UK SIM on for calls and texts, and turn data roaming off on your UK line to avoid roaming charges.

Before you buy, work out how much data you need for your trip. Think about maps, messaging, social media, video and any hotspot use. If you plan to share your connection with a laptop, check that the plan allows hotspot before you buy.

Which option suits which trip

Roaming suits short trips where you want your UK number to work with no setup. A US SIM suits longer stays where you want a US number and local data. A travel eSIM suits trips where you want data without a shop visit and want to keep your UK SIM for calls, texts and bank codes.

For a short break, roaming may be enough if your network's price is acceptable, and you avoid any setup. For a longer trip, a US SIM or a travel eSIM can give you more data for less hassle. A travel eSIM is bought online before you fly and delivered by email as a QR code, so there is no shop visit on arrival.

Whichever you choose, your phone must be unlocked and eSIM compatible if you use an eSIM. Check your network's roaming price before you travel, and decide whether you need your UK number active for calls, texts and bank codes. If you do, keep your UK SIM in the phone and use a travel eSIM for data.