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

Return flights

11 May - 18 May	TAP
04 May - 11 May	TAP
09 May - 16 May	Aer Lingus
06 May - 10 May	Aer Lingus
01 May - 08 May	Aer Lingus
07 May - 09 May	Air Canada
07 May - 10 May	Air Canada
05 May - 13 May	Aer Lingus
13 May - 18 May	Aer Lingus
08 May - 17 May	Aer Lingus
24 May - 04 Jun	Aer Lingus
25 May - 16 Jun	Air Canada
23 May - 06 Jun	Air Canada
24 May - 14 Jun	Air Canada
28 May - 01 Jun	Air Canada
25 May - 01 Jun	United
29 May - 07 Jun	Aer Lingus
24 May - 04 Jun	Finnair	direct
29 May - 07 Jun	British Airways	direct
23 May - 06 Jun	American Airlines	direct

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

Book a cheap hotel in London

Cheap car rent in London

Cheapest return flights from Boston to London in May from $447

Return flights