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

Return flights

28 Sep - 05 Oct	Air Canada
22 Sep - 15 Oct	TAP	direct
23 Sep - 30 Sep	SWISS
26 Sep - 30 Sep	SWISS
19 Sep - 30 Sep	SWISS
21 Sep - 29 Sep	SWISS
20 Sep - 29 Sep	SWISS
18 Sep - 23 Sep	SWISS
23 Sep - 29 Sep	SWISS
22 Sep - 29 Sep	SWISS
21 Sep - 30 Sep	SWISS
19 Sep - 24 Sep	SWISS
23 Sep - 01 Oct	SWISS
26 Sep - 05 Oct	SWISS
23 Sep - 08 Oct	TAP
24 Sep - 08 Oct	TAP
30 Sep - 10 Oct	Delta
25 Sep - 03 Oct	TAP
25 Sep - 17 Oct	TAP
25 Sep - 05 Oct	Air France

Also check the deals for one-way flights from Newark 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 Newark to Lisbon in September from 356€

Return flights