Cheapest return flights from Seattle to Bangkok in September from $598

Best time to book flights for Seattle (SEA) to Bangkok (BKK) flights at AirHint

AirHint found the following cheapest return flights from Seattle (SEA) to Bangkok (BKK) in September 2025 (see full year).

Return flights

11 Sep - 13 Oct Singapore Airlines
18 Sep - 27 Sep Singapore Airlines
16 Sep - 23 Sep Asiana Airlines
17 Sep - 23 Sep Asiana Airlines
22 Sep - 29 Sep China Airlines
16 Sep - 14 Oct China Airlines
03 Sep - 07 Sep China Airlines
19 Sep - 27 Sep China Airlines

Also check the deals for one-way flights from Seattle to Bangkok in September.

Skyscanner

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

Book a cheap hotel in Bangkok

Cheap car rent in Bangkok