eSIM for London: Do You Need One, and Which to Buy
If you're visiting from outside the UK and don't have a free UK roaming plan, get an eSIM installed before you fly. It takes five minutes, activates the moment you land, and means Google Maps, contactless top-ups, and last-minute ticket bookings all just work from the arrivals hall.
Why this matters more than it used to
Since Brexit, most EU mobile carriers have quietly reintroduced UK roaming charges that used to be free under EU-wide rules — so "my plan covers Europe" often no longer covers Britain. US, Australian, and most other international carriers have always charged for UK roaming, typically at steep per-day or per-MB rates. An eSIM sidesteps all of this: you buy a fixed amount of UK data upfront at a fraction of roaming prices, install it digitally, and keep your home number active for calls and texts on your primary SIM.
eSIM vs a physical UK SIM card
An eSIM is a digital SIM profile you install via QR code or app — no physical card, no shop visit, and you can set it up the night before you fly. A physical UK SIM (from Three, EE, Vodafone, or giffgaff) means finding a shop or airport kiosk after you land, and it occupies your phone's physical SIM slot, which some phones can't spare if you also want your home SIM active.
For most visitors on a trip of a few days to two weeks, the eSIM is the easier choice — set it up at home, land, and it just works. For stays of a month or more, a physical UK SIM on a rolling monthly plan can work out cheaper.
Airalo vs Holafly: which to buy
Airalo sells data in fixed packages (for example, 5GB over 30 days for the UK) — pay-as-you-go pricing that suits anyone who mostly relies on hotel or café wifi and just needs data on the move for maps, messaging, and the odd booking confirmation. It's usually the cheaper option for a typical 3–7 day city trip.
Holafly sells unlimited-data plans at a flat daily rate — better if you know you'll be hotspotting a laptop, streaming, or navigating constantly and don't want to watch a data counter. It costs more per day than Airalo's packages but removes any risk of running out mid-trip.
For the itineraries on this site — a few days of walking between attractions with maps open and the occasional GetYourGuide booking on the go — a mid-size Airalo UK package (5–10GB) comfortably covers a week's visit.
Set up your UK eSIM before you fly
Install it on wifi at home or at the departure airport, then switch it on the moment you land at Heathrow, Gatwick, or St Pancras. No kiosk queue, no physical SIM swap.
How to set it up (takes about 5 minutes)
- Check compatibility first — iPhone XS/XR or later, Pixel 3 or later, or most Galaxy S20+/Note 20+ models support eSIM. Older or budget phones often don't.
- Buy the plan on wifi — do this before you fly, since you need an internet connection to download the eSIM profile (airport wifi at your departure airport works fine if you forget).
- Install the profile — scan the QR code or use the app's one-tap install. Your home SIM stays active for calls and texts; the eSIM handles UK data only.
- Switch on arrival — turn on the UK eSIM's data line in your phone's settings the moment you land, and turn off data roaming on your home SIM to avoid accidental roaming charges.
If your phone doesn't support eSIM
Buy a physical pay-as-you-go SIM after landing. giffgaff and Three are widely regarded as the best value for short-term visitor SIMs, sold at supermarkets, phone shops, and some airport kiosks (Heathrow and Gatwick both have SIM vending machines and shops airside and in arrivals). Expect to pay roughly £10–20 for a SIM with several GB of data valid for a month — bring a passport, as UK SIM registration sometimes requires ID.
eSIM for London: Frequently Asked Questions
If you're travelling from outside the UK, almost certainly yes, unless your home carrier has a genuinely free UK roaming add-on (rare outside the EU, and many EU carriers reintroduced UK roaming charges after Brexit). Without one, you're relying on hotel and café wifi, which is patchy for navigation, contactless payment confirmations, and booking last-minute tickets on the go.
Most phones sold since 2019 do — iPhone XS and later, Google Pixel 3 and later, and most Samsung Galaxy S20+ / Note 20+ models. Check under Settings → Mobile/Cellular Data → Add eSIM (iPhone) or Settings → Network & Internet → SIMs (Android). If your phone doesn't support eSIM, a physical UK SIM card is the fallback — see below.
Airalo sells pay-as-you-go data packages (e.g. 5GB for a set number of days) — better value if you're careful with data or mostly use wifi at your hotel. Holafly sells unlimited-data plans at a flat daily rate — better if you'll be navigating, streaming, or hotspotting constantly and don't want to think about a data cap. For a typical 3–7 day London trip checking maps and messaging apps, a pay-as-you-go plan is usually enough and cheaper.
Yes — that's the main advantage over a physical SIM. Install the eSIM profile before you fly (you need wifi to download it, so do this at home or at the departure airport), then simply switch to the UK data plan when you land. No kiosk queue, no swapping physical SIM cards, and your home number stays active on your primary SIM for calls and texts.
Sometimes, for longer stays — a pay-as-you-go SIM from Three, EE, giffgaff, or Vodafone bought at a UK supermarket or airport can be very cheap for stays over 2 weeks. For short trips (under 10 days), the convenience of an eSIM you install before you fly usually outweighs the small price difference, and you avoid finding a physical shop and losing your home SIM slot for calls.