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

Return flights

16 Sep - 24 Sep	Frontier Airlines
05 Sep - 13 Sep	Frontier Airlines
16 Sep - 25 Sep	Frontier Airlines
12 Sep - 16 Sep	Frontier Airlines
06 Sep - 12 Sep	Frontier Airlines
29 Sep - 09 Oct	United
19 Sep - 03 Oct	Delta

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.

Book a cheap hotel in Lisbon

Cheap car rent in Lisbon

Cheapest return flights from Atlanta to Lisbon in September from 560€

Return flights