AirHint found the following cheapest return flights from San Juan (SJU) to London (LHR) in December 2025 (see full year).

Return flights

02 Dec - 09 Dec	British Airways
07 Dec - 14 Dec	British Airways
12 Dec - 19 Dec	United
17 Dec - 24 Dec	United
22 Dec - 29 Dec	United
20 Dec - 07 Jan	American Airlines
27 Dec - 03 Jan	United
22 Dec - 05 Jan	United

Also check the deals for one-way flights from San Juan to London in December.

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 Juan to London in December from $578

Return flights