AirHint found the following cheapest return flights from Seattle (SEA) to Shanghai (SHA) in December 2025 (see full year).

Return flights

27 Dec - 01 Jan	Korean Air
14 Dec - 30 Dec	Alaska Airlines
13 Dec - 31 Dec	Air Canada
27 Dec - 01 Jan	Delta	direct
18 Dec - 30 Dec	Air Canada
16 Dec - 01 Jan	Air Canada
15 Dec - 01 Jan	Air Canada
22 Dec - 01 Jan	Air Canada
22 Dec - 05 Jan	Korean Air
14 Dec - 02 Jan	Air Canada
15 Dec - 02 Jan	Air Canada
21 Dec - 05 Jan	ANA
14 Dec - 30 Dec	Delta	direct
19 Dec - 04 Jan	Alaska Airlines
13 Dec - 31 Dec	Delta	direct
18 Dec - 30 Dec	Delta	direct

Also check the deals for one-way flights from Seattle to Shanghai in December.

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 Shanghai in December from 1132€

Return flights