AirHint found the following cheapest return flights from Seoul (GMP) to Istanbul (IST) in September 2026 (see full year).

Return flights

15 Sep - 22 Sep	Air China
10 Sep - 17 Sep	Air China
14 Sep - 23 Sep	Air China
03 Sep - 09 Sep	Air China
05 Sep - 13 Sep	Air China
14 Sep - 11 Oct	Air China
01 Sep - 10 Sep	Air China
17 Sep - 22 Sep	Air China
17 Sep - 20 Sep	Air China
08 Sep - 17 Sep	Air China
07 Sep - 14 Sep	China Southern
01 Sep - 08 Oct	Air China
14 Sep - 09 Oct	Air China
28 Sep - 04 Oct	Air China
27 Sep - 03 Oct	China Southern
18 Sep - 01 Oct	China Southern
28 Sep - 05 Oct	China Southern
28 Sep - 09 Oct	Air China
29 Sep - 09 Oct	Air China
26 Sep - 09 Oct	Air China

Also check the deals for one-way flights from Seoul to Istanbul 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 Seoul to Istanbul in September from 543€

Return flights