Buying a UK SIM Card for Cheap: Mobile Carrier Comparisons and Other Tips

Greg Lane

Travelling without constant data these days is almost unthinkable. Getting from the station to your accommodation? You’re probably going to want to follow that little blue dot on the screen all the way to your bed for the night. Luckily, it’s all very easy.

london sim card
Photo by Gregory Lane

Keep calm and use wifi

The good news about London is that pretty much everywhere you go there’ll be some kind of open wifi network, starting with the airport. Don’t be tempted to get a SIM at the airport because there’s a good chance it won’t be the best deal available.

Do you even need a SIM?

If you’re lucky enough to be an EU resident, or you started your trip in another EU country, then Brussels has you covered; you can roam for free in London. Increasingly, non-EU mobile companies are also offering free or discounted roaming. For example, if you’re in the US on T-Mobile, free international roaming is included with “ONE”, “Simple Choice”, “New Classic” or “Select Choice” plans. Others offer low per-day roaming costs. Sometimes these roaming plans require pre-activation, so check with your mobile company before you travel.

Even if your plan does include international roaming, you might want to check the fine print—or just test performance after you arrive. Some plans are restricted to 2G data speeds (for example T-Mobile is restricted to 128Kb/s!), so getting a UK SIM might still be worth it.

How much data do you need?

As long as you login to wifi when available, you probably won’t use much more data than you use at home. If you go on a data diet, you might be able to keep yourself to 100Mb/day or less, but personally I like to have a comfortable buffer of data for those situations when you need to know if the last train is leaving from your closest station in the next 5 minutes.

Will it work in my phone?

All the big carriers in the UK sell “trio SIMs” which means no matter which one you buy, it should fit in your phone. Most modern handsets work on multiple bands, but if you’re unsure, check Will my phone work? to see which providers will work with your handset. Just to make sure, you should insert and activate your SIM in the shop where you bought it to check.

Uk sim london
Photo by Gregory Lane

UK SIM card options

The UK has plenty of mobile carriers and a healthily competitive market, which means you can get a pretty good “Pay as you go” deal. In addition to those listed below, there are also plenty of “MVNO” networks, which piggyback on the bigger networks—such as Virgin Mobile, Tesco Mobile and Giffgaff. Until the UK Brexits (and hopefully afterwards), you also get the benefit of European roaming regulations which came into effect on June 15th, 2017—so you can use your UK SIM with no additional charges throughout the remaining 27 member nations of the EU.

1GB £10.00100/3,00030 daysMore info
12GB: £20.00300/3,00030 days
Unlimited: £25.00500/3,00030 days

500MB £10.00150/Unlimited30 daysMore info
1GB: £15.00250/Unlimited30 days
4GB: £20.00500/Unlimited30 days
12GB: £30.00Unlimited/Unlimited30 days

1GB £10.00100/10030 daysMore info
2GB: £15.00750/2,00030 days
3GB: £20.001,500/4,00030 days
5GB: £25.003,000/4,00030 days
20GB: £30.003,000/4,00030 days

1GB £10.00100/1,00030 daysMore info
4GB: £15.00250/Unlimited30 days
5GB: £25.001,000/Unlimited30 days


Unless you’re a massive talk and text fiend (4,000 texts in a month while on holiday? Really?), then the £20.00, 12GB data pack from Three is the best value for money.

Written by:
London Cheapo small logo

Get all the info on what's on in London direct to your inbox.

Questions or comments about this article? Start a thread on our community forum