What an ETA covers, and for how long each stay
An ETA lets you travel to the UK, Jersey, Guernsey or the Isle of Man for up to 6 months. It is the pre-departure digital permission a visa-free visitor now needs before flying — not the trip itself.
Source: GOV.UK — UK Home Office, official ETA service page — Get an electronic travel authorisation (ETA) to visit the UK: Overview (source standing government service page; read August 8, 2026)