Are there nonstop flights from Washington (IAD) to Bangkok (DMK)?

No. The fastest connection is via Taipei, about 18h 48m of total flying time.

What is the fastest connection from Washington (IAD) to Bangkok (DMK)?

via Taipei ≈ 18h 48m, via Dubai ≈ 20h 6m, via Riyadh ≈ 20h 31m (estimated flying time, excluding layovers).

Washington Dulles International Airport (IAD) to Don Mueang International Airport (DMK)・14,134 km

No nonstop flights. The fastest connection is via Taipei (TPE), about 18h 48m of flying time (layover not included).

None.

3 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.