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

Return flights

21 Sep - 06 Oct	Air Canada
28 Sep - 05 Oct	Air Canada
22 Sep - 05 Oct	Air Canada
30 Sep - 05 Oct	Air Canada
28 Sep - 23 Oct	FrenchBee
25 Sep - 05 Oct	Austrian Airlines
30 Sep - 14 Oct	SWISS
24 Sep - 10 Oct	FrenchBee
21 Sep - 11 Oct	FrenchBee
19 Sep - 25 Sep	FrenchBee
27 Sep - 04 Oct	Scandinavian Airlines
19 Sep - 23 Sep	FrenchBee
19 Sep - 24 Sep	FrenchBee
22 Sep - 29 Sep	SWISS
25 Sep - 28 Sep	Air Canada
21 Sep - 28 Sep	FrenchBee
23 Sep - 27 Sep	TAP
19 Sep - 28 Sep	FrenchBee
19 Sep - 22 Sep	FrenchBee
21 Sep - 24 Sep	TAP

Also check the deals for one-way flights from Newark to Porto 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 Porto in September from $486

Return flights