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

Return flights

20 Sep - 27 Sep	IndiGo
12 Sep - 29 Sep	IndiGo
03 Sep - 08 Sep	IndiGo
27 Sep - 25 Oct	IndiGo
01 Sep - 06 Sep	IndiGo
30 Sep - 07 Oct	Lufthansa
18 Sep - 25 Sep	Finnair	direct
03 Sep - 08 Sep	Finnair	direct
01 Sep - 06 Sep	Finnair	direct
20 Sep - 27 Sep	Finnair	direct
30 Sep - 07 Oct	Finnair	direct

Also check the deals for one-way flights from Bangkok to Helsinki 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 Helsinki

Cheap car rent in Helsinki

Cheapest return flights from Bangkok to Helsinki in September from $761

Return flights