Are there nonstop flights from London (LHR) to Bangkok (DMK)?

No. The fastest connection is via Almaty, about 12h 17m of total flying time.

What is the fastest connection from London (LHR) to Bangkok (DMK)?

via Almaty ≈ 12h 17m, via New Delhi ≈ 12h 21m, via Hyderabad ≈ 12h 57m (estimated flying time, excluding layovers).

London Heathrow Airport (LHR) to Don Mueang International Airport (DMK)・9,548 km

No nonstop flights. The fastest connection is via Almaty (ALA), about 12h 17m of flying time (layover not included).

None.

28 one-stop options, sorted by estimated flying time. Tap one to see the airlines on each leg and booking links.

Times are estimated from distance. Check schedules, frequency and availability with the airline or a booking site.