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

Return flights

18 Sep - 23 Sep	SWISS
22 Sep - 29 Sep	Air Canada
20 Sep - 25 Sep	Icelandair
21 Sep - 26 Sep	Air Canada
19 Sep - 22 Sep	SWISS
19 Sep - 05 Oct	SWISS
30 Sep - 30 Oct	United
08 Sep - 15 Sep	Air Canada
22 Sep - 21 Oct	United
14 Sep - 19 Sep	Aer Lingus
02 Sep - 09 Sep	TAP	direct
10 Sep - 16 Sep	Air Canada
04 Sep - 16 Sep	Air Canada
27 Sep - 03 Oct	SWISS
24 Sep - 01 Oct	SWISS
23 Sep - 09 Oct	SWISS
20 Sep - 10 Oct	SWISS
19 Sep - 10 Oct	SWISS
21 Sep - 10 Oct	SWISS
24 Sep - 08 Oct	SWISS

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 308€

Return flights