As one of the world's busiest travel hubs, London's fares are shaped by heavy year-round demand — but there's still a clear seasonal pattern to when tickets get cheaper.
The cheapest months to fly
January and February consistently bring the softest fares into London, as demand drops sharply once the Christmas and New Year travel rush winds down. November also tends to be a comparatively quiet, cheaper month. Summer (June through August) and the last ten days of December are the priciest stretches by a wide margin, driven by school holidays and the Christmas travel surge.
How far ahead to book
For international flights into London, 2 to 4 months ahead is a reasonable general window, based on data across multiple major booking platforms — with some analyses pointing to a tighter 6-to-10-week sweet spot for regional European routes specifically. If your dates land anywhere in summer or around the December holidays, book earlier — by March or April at the latest for a summer trip is a safe rule of thumb, since peak-season fares climb steadily the closer you get to departure.
A routing tip worth knowing
London is served by five airports — Heathrow (LHR), the largest and main hub for long-haul international routes; Gatwick (LGW), the next-biggest option; and City (LCY), Stansted (STN), and Luton (LTN), which are smaller and often used by regional or budget carriers. Comparing fares across all five, not just Heathrow, can turn up meaningfully cheaper options, especially if you're flexible about a longer transfer into central London.
Watch out for these price spikes
- Christmas and New Year's (mid-to-late December) — one of the most expensive stretches of the year, driven by both leisure travel and family visits
- Summer (June–August) — the year's busiest period for both international and domestic UK travel, pushing fares and hotel prices up together
- Major UK and international events tied to London specifically — check event calendars if your dates are flexible, since a large concurrent event can push fares and hotel rates up even in an otherwise quieter month
The short version
January, February, and November give you the lowest general fares into London. Summer and the Christmas–New Year stretch are the most expensive by a wide margin. Book 2–4 months out for most travel, and by March or April at the latest if your dates land in summer.