United Kingdom
The UK is small, densely covered and unusually well served by mobile networks, which makes it one of the easiest places to be online. It is also expensive to roam into, which is where an eSIM earns its keep.
Coverage in practice
England, Scotland, Wales and Northern Ireland, not just the M25. The main networks cover well over ninety nine percent of the population, and coverage follows the motorways and rail lines rather than stopping at the city limits.
The places people ask about
- The Highlands. Better than its reputation on the main roads, genuinely thin in the glens. Plan for gaps on walking routes.
- The London Underground. Station platforms on much of the network now have service. Tunnels between them largely do not.
- Intercity trains. Workable, with the familiar drops through cuttings and tunnels that every passenger on every network experiences.
Why not just a local pay as you go SIM?
You can, and it is not a bad option for a few weeks. The difference is what happens afterwards: a UK prepaid SIM expires if you do not top it up, many of them cap data after a threshold, and you have to be physically in a shop to buy one. A twelve month eSIM is bought once, installed at home, and simply keeps working.
Setting it up
Install on Wi-Fi, set the eSIM as your data line, and switch data roaming on for that line. Your own number stays exactly where it is for calls and texts.