Read the country entry
A nearby island or territory can differ from the country beside it. Geographic Europe is not the same as every network’s roaming zone. Ships and aircraft may use non-terrestrial connections.
Read the allowance
Confirm duration, data fair use, eligible calls and any daily trigger. Unlimited UK data does not establish unlimited roaming. Calling overseas while still in Britain is a separate activity.
Read the settings
On a travel eSIM, choose the intended data line and inspect whether the UK line can still incur other charges. Download useful maps beforehand. Turning off data roaming does not block every voice or message charge.