There are 34 direct and indirect flights connecting Southampton and Tokyo every week, with the journey taking 24 hrs 10 mins on average.
Or, if you're fairly flexible on dates, try to get a last minute-deal by regularly checking the Netflights website.
Tokyo actually has two airports to choose from – but New Tokyo International Airport (NRT) is the usually the cheapest option. If you need to fly into a specific airport, adjust your search to focus on those flights. The most popular airlines include Cathay Pacific, Singapore Airlines & Etihad Airways.
If you can’t find flights that suit you, consider flying to a another part of Japan.