Avoid high roaming charges when traveling to Europe and buy a UK sim card on arrival at London Heathrow! It is the cheapest way to stay connected and it doesn't cost as much as you may think. In this complete guide for buying a UK sim card at London Heathrow I tell you where to buy a sim card, up to date prices as per June 2022, my recommendation and even give you info about international and e-sim cards for the UK.