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

Return flights

07 Sep - 23 Sep	Air France
07 Sep - 12 Sep	Air France
08 Sep - 12 Sep	Air France
21 Sep - 01 Oct	Air France
22 Sep - 14 Oct	Air France
23 Sep - 14 Oct	Air France
21 Sep - 14 Oct	Air France
25 Sep - 05 Oct	KLM
20 Sep - 14 Oct	Air Transat
22 Sep - 24 Sep	Porter Airlines (Canada) Ltd
15 Sep - 27 Sep	Air France
26 Sep - 06 Oct	Air Canada
26 Sep - 04 Oct	WestJet
20 Sep - 27 Sep	Air Canada

Also check the deals for one-way flights from Ottawa 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 Ottawa to Lisbon in September from 526€

Return flights