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

Return flights

06 May - 10 May	SWISS
07 May - 17 May	Aer Lingus
04 May - 13 May	Aer Lingus
05 May - 19 May	Aer Lingus
14 May - 17 May	Aer Lingus
02 May - 09 May	Aer Lingus
04 May - 07 May	Aer Lingus
08 May - 14 May	Aer Lingus
11 May - 18 May	SWISS
11 May - 20 May	SWISS
15 May - 01 Jun	Aer Lingus
15 May - 02 Jun	Air Canada
15 May - 01 Jun	British Airways	direct
15 May - 02 Jun	British Airways	direct
20 May - 03 Jun	Aer Lingus
29 May - 10 Jun	SWISS
29 May - 13 Jun	SWISS
22 May - 02 Jun	Air Canada
26 May - 04 Jun	Aer Lingus
23 May - 06 Jun	Air Canada

Also check the deals for one-way flights from London to San Francisco 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 London to San Francisco in May from 411€

Return flights