High season is considered to be January, February and December. The cheapest month to fly from London to Japan is January. Morning departure is around 4% more expensive than an evening flight, on average*. A heavily used airport in Japan is Tokyo International Airport (HND), otherwise known as Haneda Airport.

Generally, the cheapest time to fly from London to Japan is during the late autumn and winter months, specifically November and January through early March. During these periods, you can often find round-trip fares for significantly less than the peak spring (Cherry Blossom) or summer (holiday) seasons. November is particularly recommended because the weather is still mild and the fall foliage is stunning, but the "Golden Week" and summer crowds have vanished. Conversely, July and August are typically the most expensive months due to school holidays and the humidity, while late March and April see a price surge as tourists flock to see the Sakura. To find the absolute lowest prices in 2026, many travelers look for indirect flights with a stop in mainland China or the Middle East, which can sometimes be 40% cheaper than a direct British Airways or JAL flight. Booking at least 3–4 months in advance for these "off-peak" windows is the most reliable way to secure a budget-friendly fare to Tokyo or Osaka.