Prepaid SIM card UK: where to buy one and which to choose in 2026

Landing in the UK and need a prepaid SIM card? Here's the fast answer: you can buy a physical SIM in shops, supermarkets, online or directly from the networks, or skip the card and install a prepaid Three UK eSIM before you fly. Sim Local's Three UK plans start for less than a lunch for 20GB and include a UK number, unlimited local calls and texts, 5G and roaming data in 70+ destinations.

A prepaid SIM, also called pay as you go (PAYG), lets you pay for what you use instead of signing a contract. There is no monthly bill and no credit check, which is why it suits visitors. On a traditional UK PAYG SIM you add credit with top-up vouchers, usually sold in £5 increments online or in shops.

Pay-per-use rates still exist (giffgaff's SIM page, for instance, lists pay-as-you-go rates of 25p a minute), but most visitors pick a bundle instead: a fixed amount of data, minutes and texts for 30 days. That is also how the Three UK plans below work.

Two questions come up again and again. Does a prepaid SIM card come with a phone number? Yes: a new SIM gives you a new number, which is why you should keep your home SIM safe, and why the eSIM route is handy, because your home SIM stays in your phone. And can you use your phone without a SIM card? If your phone supports eSIM, yes. The plan installs digitally, so there is no card to insert at all.

For short visits, Uswitch's UK SIM guide says a travel eSIM "might make more sense than a dedicated UK SIM".

Before you buy anything, five quick checks save most of the usual problems:

• Is your phone unlocked? A phone locked to your home network will not accept a UK plan. Here's how to check and unlock your phone.
• Does it support eSIM? Most recent iPhones and Android flagships do. Our iPhone eSIM guide covers compatibility and setup, and Sim Local has a compatibility checker.
• How much data do you need? Sim Local's own estimate is 5-10GB for a week of maps, messaging and email. Independent travel guides put light use lower, at roughly 1-6GB a week. If you stream or tether, plan higher, and see our guide to how much data you need when travelling.
• Do you want to keep your home number? With an eSIM, you can. Your phone runs both lines, as we explain in what a dual SIM phone is and why you may not need one. It also keeps two-factor codes and banking texts arriving.
• Does your home plan roam? Travel guides note that SIMs bought in EU countries may not work, or may cost extra, in the UK since Brexit. How to avoid roaming charges explains your options.

You have six routes. Which one wins depends on whether you want to pay in person or order before you fly.

• High-street shops. Network stores and phone retailers sell physical SIMs. Carrier shops tend to offer the most help; smaller retailers often offer little support.
• Supermarkets and newsagents. Travel guides list Tesco, Sainsbury's and Asda among the places that sell cheap PAYG SIMs for short trips.
• Online stores and marketplaces. Third-party sellers list Three-network SIMs, for example a 30-day bundle of 12GB with 3,000 minutes and 3,000 texts. The card has to be shipped to you, so order well ahead of your flight.
• Directly from the networks. giffgaff lets you order a free PAYG SIM online. Vodafone lists Pay as you go Plus plans from £10 (27GB for the first three months with auto-renew) up to £40 for unlimited data, with eSIM on every plan.
• At the airport. One long-running travel guide warns that tourist hubs such as airports and train stations can carry pricier plans. Sim Local announced stores in the arrivals and baggage halls at Heathrow selling local SIM cards and eSIMs; the Heathrow store announcement has the locations.
• Online, before you travel. This is the one that works from anywhere. If you're searching from the US, Australia or New Zealand, a UK eSIM can be bought online and installed before you leave. Sim Local's Three UK plans arrive by email straight after purchase, so there is nothing to ship or collect.

The catch with any physical SIM is timing: you need it in your hands before you can use it. With an eSIM you can buy the night before you fly and install it in about three minutes.

Both work on the same UK networks. The difference is how you get set up. For a longer look, see eSIM vs physical SIM: which is better?.

How to buy a UK prepaid SIM card in 2026

• Check your phone. It needs to support eSIM and be unlocked. The compatibility checker on Sim Local confirms this before you buy.
• Pick a plan. Compare the five Three UK options below.
• Buy online. You'll receive a 4-digit confirmation code and download instructions by email straight away. Our five-step guide to buying an eSIM online walks through it.
• Install. Download the plan with one click in the Sim Local app, or scan the QR code. iPhone users can follow the step-by-step install guide.
• Activate when you arrive. Sim Local recommends activating as soon as you land in the UK.

Keep your home SIM in the phone as well. Your usual number stays active for calls and texts, while the eSIM handles UK data and gives you a UK number.

It depends on how much data you use, but for visitors our pick is a Three UK eSIM from Sim Local. You get a local UK number, unlimited local calls and texts, 5G where available, hotspot and roaming data, all without waiting for a card to arrive.