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

Return flights

31 Aug - 07 Sep	Philippine Airlines
17 Aug - 27 Sep	Philippine Airlines
18 Aug - 27 Sep	Air Canada
30 Aug - 26 Sep	Singapore Airlines
23 Aug - 25 Sep	Air Canada
24 Aug - 31 Aug	Philippine Airlines
16 Aug - 27 Sep	Asiana Airlines
12 Aug - 24 Aug	Asiana Airlines
13 Aug - 17 Aug	United
12 Aug - 22 Aug	United
08 Aug - 20 Aug	United
09 Aug - 21 Aug	United
02 Aug - 19 Aug	Korean Air
08 Aug - 24 Aug	Korean Air
09 Aug - 17 Aug	United
02 Aug - 17 Aug	United

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 $696

Return flights