AirHint found the following cheapest return flights from Seattle (SEA) to Taipei (TPE) in September 2025 (see full year).

Return flights

14 Sep - 21 Sep	Asiana Airlines
23 Sep - 27 Sep	Asiana Airlines
23 Sep - 29 Sep	Asiana Airlines
22 Sep - 30 Oct	Asiana Airlines
15 Sep - 22 Sep	Asiana Airlines
17 Sep - 24 Sep	Philippine Airlines
29 Sep - 30 Oct	Asiana Airlines
21 Sep - 30 Oct	Asiana Airlines
25 Sep - 28 Sep	Asiana Airlines
17 Sep - 24 Sep	Delta	direct
11 Sep - 18 Sep	Delta	direct
15 Sep - 22 Sep	Delta	direct
23 Sep - 29 Sep	Delta	direct
29 Sep - 30 Oct	Delta	direct
24 Sep - 15 Oct	Delta	direct
22 Sep - 30 Oct	Delta	direct
21 Sep - 30 Oct	Delta	direct
13 Sep - 13 Oct	Delta	direct

Also check the deals for one-way flights from Seattle to Taipei 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 Seattle to Taipei in September from 529€

Return flights