Connecting through LHR - Visa?
 

Hey there-

I know this isn't exactly Delta-centric, but I am flying Delta and I typically rely on Delta.com to tell me what documents I have to complete before traveling. For this trip, we are flying ATL-LHR (Delta metal) and connecting to LHR-CPH (SAS Metal). We're planning to check bags all the way through, etc.

Do we have to get the new UK visa form thing or only if we have to go through security in the UK? If we land at Terminal 3 and leave from Terminal 2, do we have to leave/go through immigration?

A UK ETA is not required for international-international transit at LHR (however, if there is a disruption having a UK ETA can be helpful). You will not need to go through immigration at LHR. When you land at T3, follow the purple flight connection signs which will lead you to the bus to T2. On arrival at T2, you will have to go back through security, but you won't have to go through immigration.

I was in your situation but I got it in case of IROPS and I had to sleep in UK instead of the airport. It was cheap (16£) and took 5 minutes online.

An ETA is not a visa !