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

Return flights

23 Sep - 08 Oct	Aer Lingus
22 Sep - 08 Oct	Aer Lingus
29 Sep - 15 Oct	Aer Lingus
23 Sep - 15 Oct	Aer Lingus
24 Sep - 08 Oct	Condor
08 Sep - 26 Sep	Condor
23 Sep - 01 Oct	Turkish Airlines
15 Sep - 11 Oct	British Airways
09 Sep - 26 Sep	Condor
09 Sep - 16 Sep	Condor
29 Sep - 28 Oct	Turkish Airlines
23 Sep - 18 Oct	Turkish Airlines
17 Sep - 23 Sep	Condor
14 Sep - 04 Oct	Lufthansa
10 Sep - 26 Sep	Condor
08 Sep - 15 Sep	Condor
08 Sep - 14 Sep	Condor
16 Sep - 29 Sep	Alaska Airlines
06 Sep - 13 Sep	Condor
16 Sep - 30 Sep	Condor

Also check the deals for one-way flights from Seattle to Rome 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 Rome in September from $567

Return flights