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

Return flights

13 Sep - 18 Sep	KLM
22 Sep - 25 Sep	KLM
12 Sep - 16 Oct	Luxair
27 Sep - 07 Oct	Luxair
22 Sep - 30 Sep	KLM
16 Sep - 24 Sep	SWISS
23 Sep - 25 Sep	Luxair
16 Sep - 18 Sep	SWISS
17 Sep - 18 Sep	SWISS
17 Sep - 19 Sep	ITA Airways
26 Sep - 11 Oct	Luxair
02 Sep - 10 Sep	SWISS
26 Sep - 03 Oct	Luxair
14 Sep - 17 Sep	British Airways
27 Sep - 15 Oct	Luxair
26 Sep - 18 Oct	Luxair
26 Sep - 19 Oct	Luxair
27 Sep - 18 Oct	Luxair
27 Sep - 02 Oct	Luxair
29 Sep - 12 Oct	Luxair

Also check the deals for one-way flights from London 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.

Book a cheap hotel in Porto

Cheap car rent in Porto

Cheapest return flights from London to Porto in September from 292€

Return flights