London (LHR) to Bangkok (BKK): 5,951 miles (9,578 km) great-circle, about 12h 25m nonstop by our estimate. Cheapest fare observed: $690 round-trip on Saudia, with 1 stop, departing April 29, 2026.
$690 round-trip, Saudia SV110, departing 2026-04-29 at 10:10, returning 2026-05-09. The recorded itinerary left on a Wednesday, returning on a Saturday 10 nights later; the fare was observed 4 days before departure. "Book this flight" opens Kiwi.com with the same airline and dates.
At $690, it ranked 20th of the 30 round-trip fares we recorded from LHR (median $624). That is 11.6 cents per great-circle mile (round-trip price over one-way distance), below the LHR median of 22.9 cents across 30 round-trip routes.
Routes from LHR of similar length: Malé (5,306 mi) at $831 and Beijing (5,067 mi) at $717.
Saudia had the cheapest fare on 2 of 30 LHR routes. It is the longest of the 30 routes we track from LHR.
Of 59 departure airports with a fare to Bangkok, London (LHR) ranked 42nd at $690. Lowest: $73 from Phuket (HKT); highest: $1428 from Mexico City (MEX); 14 nonstop. Cheapest-fare airlines (routes): Air India (5), Etihad (5), Thai Vietjet Air (4), Air China (3), Scoot (3) and Thai AirAsia (3), plus 31 more.
Travelpayouts fares (cheapest per route, observed April 25, 2026); OurAirports coordinates and elevations; IANA zones Europe/London, Asia/Bangkok; flight time is our estimate.