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

Return flights

04 Sep - 17 Sep	SWISS
18 Sep - 30 Sep	SWISS
17 Sep - 29 Sep	SWISS
06 Sep - 16 Sep	Austrian Airlines
23 Sep - 30 Sep	Ryanair
24 Sep - 13 Oct	Ryanair
10 Sep - 15 Sep	Ryanair
10 Sep - 18 Sep	Ryanair
16 Sep - 01 Oct	Ryanair
19 Sep - 05 Oct	Ryanair
10 Sep - 14 Sep	Ryanair
17 Sep - 25 Sep	Ryanair
11 Sep - 15 Sep	Ryanair
30 Sep - 10 Oct	Ryanair
26 Sep - 04 Oct	Ryanair
20 Sep - 04 Oct	Ryanair
20 Sep - 05 Oct	easyJet
28 Sep - 30 Oct	Air Europa
29 Sep - 30 Oct	Air France
26 Sep - 30 Oct	SWISS

Also check the deals for one-way flights from Porto 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.

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Cheapest return flights from Porto to Bangkok in September from $676

Return flights