AirHint found the following cheapest return flights from Seattle (SEA) to Singapore (SIN) in August 2025 (see full year).

Return flights

21 Aug - 24 Aug	Asiana Airlines
28 Aug - 31 Aug	Asiana Airlines
19 Aug - 29 Aug	Asiana Airlines
12 Aug - 24 Aug	Asiana Airlines
18 Aug - 28 Aug	United
20 Aug - 27 Aug	Asiana Airlines
21 Aug - 28 Aug	United
14 Aug - 17 Aug	Asiana Airlines
17 Aug - 27 Aug	Asiana Airlines
17 Aug - 21 Aug	Asiana Airlines
22 Aug - 08 Sep	Korean Air

Also check the deals for one-way flights from Seattle to Singapore 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 Seattle to Singapore in August from $708

Return flights