Cheapest return flights from Chicago to Seattle in September from $91

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

Return flights

10 Sep - 24 Sep Alaska Airlines direct
09 Sep - 23 Sep Alaska Airlines direct
09 Sep - 30 Sep Alaska Airlines direct
10 Sep - 01 Oct Alaska Airlines direct
23 Sep - 14 Oct Alaska Airlines direct
16 Sep - 07 Oct Alaska Airlines direct
30 Sep - 21 Oct Alaska Airlines direct
30 Sep - 07 Oct Alaska Airlines direct
16 Sep - 14 Oct Alaska Airlines direct
23 Sep - 21 Oct Alaska Airlines direct
16 Sep - 23 Sep Alaska Airlines direct
17 Sep - 25 Sep Alaska Airlines direct
16 Sep - 11 Oct Alaska Airlines direct
30 Sep - 25 Oct Alaska Airlines direct
30 Sep - 27 Oct Alaska Airlines direct
17 Sep - 20 Sep Alaska Airlines direct
03 Sep - 17 Sep United direct
02 Sep - 16 Sep United direct
03 Sep - 30 Sep United direct
18 Sep - 20 Sep Alaska Airlines direct

Also check the deals for one-way flights from Chicago to Seattle in September.

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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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