When I leave England I will fly out of LHR on Delta Airlines, Terminal 3. I will have to check one suitcase. Does LHR Terminal 3 Delta have curbside baggage check like many US airports do? Does Delta have check-in kiosks? Or will I need to go to a counter agent/
How are you getting there? Most people use the tube and thus don’t even see the outside of the airport.
No curbside checkin. You have to go to the counter. Sometimes there is a second layer of screening done on passengers bound for the US. Last year when flying Delta from LHR Everyone in line to drop bags had to speak with an agent and answer questions (Where have you traveled, did you pack your own bag, have they been out of your control, etc) before you got to the gate agent. Give yourself some extra time for check in. Be to the airport at least 3 hours before your flight.
We take the underground to LHR Term 3 and fly Delta back home. If I'm not completely mistaken, we come out of the underground on the escalator up to the outside and to the left a few yards away is the door to Term 3. Delta is inside. You need to go to the counter with your luggage to check it. We have never had a long wait and check in has gone smoothly.
I plan to get there on the Heathrow Express. I'll have one full size suitcase, one carry on, and a personal item. I thought that would be a bit much to lug around on the tube.
Heathrow Express is also a train, you will not be at a "kerb" (UK spelling).
I have seen this "kerbside check-in" thing on US films, never seen it in Europe. Perhaps it is to do with the preferred method of getting to the airport being public transport. Driving there is discouraged.
There are usually luggage trolleys you can use to wheel your bags to the correct check-in desk. Frankly, with only one case, assuming it has wheels it will be simpler just to wheel it.