A prepaid UK eSIM from eSpeedz starts at $7.99 for 30 days of data, with plans from 5GB to 50GB that work across England, Scotland, Wales and Northern Ireland. You get a QR code by email within minutes, install it before your flight, and it connects once you land in the UK.
Walk off the plane at Heathrow with maps and Citymapper already working, and skip the daily roaming fee on your US plan.
London runs on contactless. You tap your phone or card on the Tube and buses, black cabs take card, and so do most pubs and market stalls. That makes your phone your wallet, map and ticket all at once, so losing data hurts more here than in most cities. Paying AT&T or Verizon $12 a day for that connection adds up fast on a 10-day trip, and T-Mobile's included basic data at up to 256kbps makes Citymapper feel like dial-up.
Picking up a UK SIM is simple compared with much of Europe, since you won't need to register it with your passport. It's still an errand for your first afternoon, though, and if your trip continues to Paris, Dublin or Amsterdam, UK SIMs are no longer covered by the EU's free roaming rules. An eSIM installed at home means you're connected from the jet bridge.
Wifi is easy to find in hotels, cafes and chain restaurants. Underground, the whole Elizabeth line has mobile signal and TfL has been switching on 4G and 5G across Tube stations and tunnels, aiming to cover the full network by the end of 2026. The gaps are outside the cities: the Scottish Highlands, mid-Wales and parts of the Lake District can drop to one bar or none, so download offline maps before any road trip.
Plans connect to leading local 4G/5G networks in the United Kingdom. Data-only, prepaid, no contract. Prices in USD.
| Plan | Data | Validity | Price (USD) |
|---|---|---|---|
| United Kingdom 5GB | 5GB | 30 days | $7.99 |
| United Kingdom 10GB | 10GB | 30 days | $13.99 |
| United Kingdom 20GB | 20GB | 30 days | $26.99 |
| United Kingdom 50GB | 50GB | 30 days | $56.99 |
| UK + Ireland 5GB | 5GB | 7 days | $14.99 |
| UK + Ireland 10GB | 10GB | 15 days | $27.99 |
| UK + Ireland 20GB | 20GB | 30 days | $55.99 |
Prices checked October 1, 2026. All prices in USD, one-time payment.
| Network | Leading local 4G/5G networks in the United Kingdom |
|---|---|
| Phone number | Not included. Data only, your regular number keeps working for calls and texts |
| Validity starts | When the eSIM first connects in the United Kingdom, not when you buy or install it |
| Delivery | QR code by email, usually in about 3 minutes |
| Top-ups | Available |
| Phone needed | eSIM-compatible and carrier-unlocked |
| Multi-country option | UK + Ireland |
Plans connect to leading local 4G/5G networks in the United Kingdom. Popular stops for travelers:
London uses more data than you'd think because you're navigating constantly: Citymapper, Google Maps, theater tickets, restaurant bookings and rideshare apps. For one week, 5GB is comfortable for most visitors. For two weeks with day trips to Bath, Oxford or Edinburgh and lots of photo sharing, 10GB gives you breathing room. If you'll be streaming football in the pub or working from cafes, look at 20GB or 50GB.
May through September brings the longest days and your best odds of dry weather, though dry is relative here. August is festival month in Edinburgh, which means great energy and very high hotel prices. London works year-round, with Christmas lights and markets in December, and the countryside is at its prettiest in late spring when everything turns green.
Sources: gov.uk · att.com · verizon.com · t-mobile.com · tfl-newsroom.prgloo.com · timeout.com. Information checked October 2026. Entry rules and fees change, so confirm with official sources before you travel.