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

Return flights

17 Sep - 21 Sep	Etihad Airways
17 Sep - 25 Sep	Etihad Airways
16 Sep - 23 Sep	SWISS
18 Sep - 21 Sep	Turkish Airlines
01 Sep - 01 Oct	Etihad Airways
16 Sep - 25 Sep	KLM
07 Sep - 11 Sep	Turkish Airlines
07 Sep - 15 Sep	Turkish Airlines
16 Sep - 21 Sep	KLM
15 Sep - 22 Sep	Turkish Airlines
16 Sep - 27 Sep	KLM
11 Sep - 07 Oct	Turkish Airlines
29 Sep - 05 Oct	Air France
01 Sep - 04 Oct	Finnair
23 Sep - 08 Oct	Lufthansa
01 Sep - 31 Oct	Etihad Airways

Also check the deals for one-way flights from Singapore 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 Singapore to Lisbon in September from $707

Return flights