AirHint found the following cheapest return flights from San Jose (SJC) to London (LGW) in September 2025 (see full year).

Return flights

26 Sep - 29 Sep	Frontier Airlines
28 Sep - 18 Oct	Hawaiian Airlines
29 Sep - 14 Oct	Icelandair
27 Sep - 07 Oct	Icelandair
25 Sep - 07 Oct	Icelandair
21 Sep - 11 Oct	Frontier Airlines
17 Sep - 20 Oct	Icelandair
15 Sep - 11 Oct	Icelandair
16 Sep - 11 Oct	Icelandair
20 Sep - 11 Oct	Icelandair
17 Sep - 11 Oct	Icelandair
23 Sep - 30 Sep	Icelandair
16 Sep - 27 Sep	Icelandair
16 Sep - 30 Sep	Icelandair

Also check the deals for one-way flights from San Jose to London 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 San Jose to London in September from $793

Return flights