AirHint found the following cheapest return flights from Atlanta (ATL) to Lisbon (LIS) in September 2025 (see full year).

Return flights

29 Sep - 07 Oct	Spirit Airlines
28 Sep - 06 Oct	Spirit Airlines
30 Sep - 08 Oct	Air France
23 Sep - 30 Sep	United
23 Sep - 01 Oct	United
25 Sep - 02 Oct	Spirit Airlines
24 Sep - 02 Oct	Spirit Airlines
29 Sep - 03 Oct	Spirit Airlines
25 Sep - 03 Oct	Turkish Airlines
24 Sep - 01 Oct	Lufthansa
27 Sep - 05 Oct	Frontier Airlines
20 Sep - 25 Sep	Turkish Airlines
20 Sep - 27 Sep	Spirit Airlines
17 Sep - 24 Sep	Frontier Airlines
16 Sep - 24 Sep	United

Also check the deals for one-way flights from Atlanta to Lisbon 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 Atlanta to Lisbon in September from 490€

Return flights