Cheapest return flights from Seattle to Barcelona in September from $481

Best time to book flights for Seattle (SEA) to Barcelona (BCN) flights at AirHint

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

Return flights

01 Sep - 09 Sep Scandinavian Airlines
10 Sep - 23 Sep Scandinavian Airlines
03 Sep - 10 Sep Aer Lingus
23 Sep - 30 Sep Air Canada
02 Sep - 08 Sep British Airways
15 Sep - 22 Sep British Airways
19 Sep - 26 Sep Air Canada
13 Sep - 04 Oct Iberia
14 Sep - 21 Sep British Airways
11 Sep - 29 Sep American Airlines

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

Skyscanner

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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