LHR transfer time

LHR says 20 minutes. https://www.heathrow.com/at-the-airport/airport-maps/travel-between-terminals?searchInput=predictive

Don't believe it. I have never gotten between any two points at LHR in under 45 min. You are on separate tickets? I would do Tuesday and Wednesday.

Yes, it would be separate tickets. We would be arriving from SEA and connecting to ATH. We would have no checked bags.

https://www.heathrow.com/connecting-flights has a calculator - put in incoming and outgoing flights.

Personally, I don't think I'd feel comfortable with anything less than 3 hours. Arrive, go through immigration (I'd allow an hour to 90 minutes), transfer between terminals (30 minutes) and leave enough time boarding (90 minutes).

No checked bags is a big plus, because you should be able to follow the same transfer procedure as if your flights were on the same reservation. You should not need to go through UK passport control, and you should be able to do the entire transfer airside. One thing that will facilitate your connection is if you can have your connecting boarding pass in hand when you arrive at Heathrow - which means checking in for the connecting flight before you leave Seattle.

For flights to and from those terminals on the same reservation, the minimum connection time is (usually?) 90 minutes. In my experience, that's about right - that's exactly how long it takes to get from point A to point B and arrive at the connecting gate in the nick of time, right as your flight is closing. Most likely, you'll want a considerably longer layover than that, to give you some cushion in case things go moderately wrong. How much of a cushion you need depends on your personal tolerance for risk, and how difficult/expensive it would be for you to arrange alternative transportation to Athens in the event that you miss your connection.

>Meeting of the minds?**

I understand Kevin's question to be "how much time should I allow between the scheduled arrival time of my 1st flight and the departure time of the 2nd flight'?; not "how long does it take to traverse the distance between terminals?"

20 minutes is the answer to the latter.

The answer ( or likely the consensus) for the former is 3 + hrs.

This link may be helpful https://www.heathrow.com/connecting-flights Plug in your flight info for an idea.

Yea, I read what the website said. 20 minutes. In May last year I did a T5 to T3 transfer, also stated to be 20 minutes. From arrival to departure gate took every bit of 1.5 hours thanks to security and a bus. Plan on being .5 hours late, then there is an hour prior to boarding check-in and it amounts to 3 hours. I have done a lot of 3 hour layovers at LHR and there really hasn't been a lot of free time involved. Horrible airport. Only Chucky D is worse. If I had to use separate tickets I would use the opportunity to see London for a day; cause I would want at least a 4 hour lay over to protect my investment and I dont do 4 hour lay overs.....