Heathrow eSIM and Wi-Fi: UK Arrival Data Checklist

How do I use airport Wi-Fi?

Follow Heathrow’s official Wi-Fi instructions. Airport Wi-Fi can help retrieve messages or installation details in the terminal, but it does not provide mobile service for the journey into London.

Which plan fits London and the rest of my trip?

Compare current total and daily allowances with the dates you need data. For Ireland or onward Europe, confirm every country explicitly. A UK product should not be assumed to include those stops. London trip examples explain minimum allowance and validity choices.

What should I prepare before arrival?

Save your transfer booking, accommodation address and installation details offline. check your exact device, follow the supplied start rules and select the travel line for data. Check home-carrier charges separately for calls, SMS and roaming. Use plan-specific support instructions if connection fails.

See each step on iPhone and Android

Use the walkthrough to see how buying in the Graba SIM app, installing on Wi-Fi and choosing your data line look on your own type of phone. Screens are illustrations: menu names vary by phone, software version and region.

Protect your home SIM from roaming charges

Switch roaming off on your usual line before you leave home, not after landing, so your phone cannot use your home provider’s roaming data when it first connects abroad. Then switch the travel eSIM on when you arrive.

• Before you fly, iPhone: Settings → Mobile Service (or Cellular) → your usual line → turn Data Roaming off. Keep mobile data on that line until you land.
• Before you fly, Android: Settings → Network & internet → SIMs → your usual SIM → turn Roaming off. On Samsung, start in Settings → Connections → SIM manager.
• When you land: open the travel eSIM line, make sure it is on and turn its Data Roaming (or Roaming) on. Then choose the travel eSIM for mobile data and turn off automatic data switching.

These settings control mobile data only. Your home provider may still charge for calls, texts or other services, so check its terms. Read the roaming settings guide.

Choose your next step

UK eSIM plans and London eSIM buying guidance.

Reviewed 16 October 2026 using current product information and the sources linked above. This is planning guidance, not a claim of independent network testing. Check the selected plan’s current price, coverage and activation terms before purchase.