In February 2019 I took a trip to London to find the best UK sim card for tourists. For those traveling to the UK and do not want to spend a lot of money on roaming costs. For about £20 you can already get 10GB data! When arriving at the London Airports: Heathrow, Gatwick, Stansted and Luton you might want to buy your UK sim card there. Click on your London Airport for a detailed guide.