UK eSIM guide: mobile data in London and across Britain
A travel eSIM gives you mobile data in the UK for the Tube, trains and maps as soon as you arrive. Since Brexit, many EU carriers charge roaming fees in the UK again, which makes a travel eSIM a useful alternative.
Mobile networks in the United Kingdom
The UK's main operators are EE, O2 and VodafoneThree (formed when Vodafone and Three merged in 2025). Coverage is strong in London and other cities, with 5G in many urban areas.
Signal can be limited in the Scottish Highlands, parts of Wales, national parks and some rural roads. Many London Underground stations and some tunnel sections now have mobile coverage.
How much data do you need in the UK?
A London city break with maps, transport apps and messaging usually needs 3 to 5 GB per week. A road trip through Scotland or the countryside is more comfortable with 10 GB.
Practical tips for the UK
- Contactless payment works on London public transport, but journey planners need data.
- Book train tickets in advance online; fares are often cheaper and tickets can be stored on your phone.
- Download offline maps for the Highlands and national parks.
- Check whether your home carrier charges roaming in the UK before you rely on it.
Setting up your eSIM before departure
Install the eSIM at home on Wi-Fi. When you arrive, activate the eSIM line, enable data roaming for it and choose it for mobile data.