AirHint found the following cheapest return flights from San Francisco (SFO) to London (LHR) in May 2026 (see full year).

Return flights

05 May - 13 May	Air Canada
04 May - 13 May	SWISS
03 May - 08 May	Aer Lingus
04 May - 12 May	Iberia
01 May - 22 May	Air Canada
05 May - 10 May	Air Canada
13 May - 29 May	Air Canada
11 May - 01 Jun	Air Canada
05 May - 13 May	Air France	direct
04 May - 13 May	Air France	direct
07 May - 15 May	Air Canada
20 May - 01 Jun	Air Canada
19 May - 02 Jun	ITA Airways
19 May - 02 Jun	Air France	direct
23 May - 03 Jun	TAP
25 May - 05 Jun	WestJet
24 May - 05 Jun	Air Canada
24 May - 03 Jun	Scandinavian Airlines
26 May - 15 Jun	TAP
27 May - 02 Jun	Scandinavian Airlines

Also check the deals for one-way flights from San Francisco to London in May.

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 Francisco to London in May from $619

Return flights