AirHint found the following cheapest return flights from Chiang Rai (CEI) to Seoul (ICN) in September 2025 (see full year).

Return flights

14 Sep - 21 Sep	Thai AirAsia
14 Sep - 19 Sep	Thai AirAsia
02 Sep - 21 Sep	Thai AirAsia
16 Sep - 21 Sep	Thai AirAsia
02 Sep - 19 Sep	Thai AirAsia
16 Sep - 19 Sep	Thai AirAsia
14 Sep - 17 Sep	Thai AirAsia
14 Sep - 22 Sep	Thai AirAsia
02 Sep - 17 Sep	Thai AirAsia
02 Sep - 22 Sep	Thai AirAsia
30 Sep - 18 Oct	Thai AirAsia
30 Sep - 20 Oct	Thai AirAsia
29 Sep - 06 Oct	Thai VietJet Air
16 Sep - 06 Oct	Thai AirAsia
14 Sep - 01 Oct	Thai AirAsia
16 Sep - 01 Oct	Thai AirAsia
30 Sep - 06 Oct	Thai AirAsia
14 Sep - 03 Oct	Thai AirAsia
16 Sep - 03 Oct	Thai AirAsia
30 Sep - 03 Oct	Thai AirAsia

Also check the deals for one-way flights from Chiang Rai to Seoul 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 Chiang Rai to Seoul in September from 274€

Return flights