AirHint found the following cheapest return flights from St. Louis (STL) to Seoul (ICN) in August 2025 (see full year).

Return flights

29 Aug - 31 Aug	Delta
19 Aug - 26 Aug	Delta
17 Aug - 29 Aug	Delta
28 Aug - 29 Sep	Delta
28 Aug - 30 Sep	Delta
29 Aug - 30 Sep	Delta
30 Aug - 30 Sep	Delta
29 Aug - 29 Sep	Delta
08 Aug - 19 Aug	United
09 Aug - 19 Aug	United

Also check the deals for one-way flights from St. Louis to Seoul in August.

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 St. Louis to Seoul in August from 745€

Return flights