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

Return flights

10 Sep - 11 Sep	Jeju Air
17 Sep - 25 Sep	Jeju Air
17 Sep - 18 Sep	Jeju Air
07 Sep - 11 Sep	T'way Air
24 Sep - 25 Sep	Jeju Air
09 Sep - 18 Sep	Jeju Air
06 Sep - 25 Sep	Jeju Air
09 Sep - 16 Sep	Korean Air
10 Sep - 18 Sep	Jeju Air
13 Sep - 18 Sep	Jeju Air
24 Sep - 04 Oct	Jeju Air
24 Sep - 01 Oct	Jeju Air
24 Sep - 03 Oct	Jeju Air
23 Sep - 03 Oct	Jeju Air
27 Sep - 02 Oct	Eastar Jet
27 Sep - 01 Oct	Jeju Air
27 Sep - 04 Oct	Jeju Air
26 Sep - 01 Oct	Jeju Air
26 Sep - 02 Oct	Jeju Air
27 Sep - 03 Oct	Jeju Air

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

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

Cheapest return flights from Seoul to Bangkok in September from $209

Return flights