Tokyo is UTC+9 (GMT+9, no DST). London is UTC+0 (GMT) / UTC+1 (GMT+1). London is currently 8 hours behind Tokyo.
There is no overlap of standard business hours (09:00–17:00) between these two cities. Consider early morning or late afternoon calls where one side works slightly outside core hours.
Times shown in Tokyo local time → London local time. Based on business hours 09:00–17:00.
Tokyo observes Japan Standard Time (JST, UTC+9) year-round. Japan abolished Daylight Saving Time in 1951, after experimenting with it during the post-war US occupation (1948–1951), and has not reinstated it since. The fixed UTC+9 offset means that Tokyo's sunrise and sunset times shift significantly across seasons — the sun rises before 04:30 in late June and after 06:50 in late December — but the clock never moves. Japan Standard Time is shared by the entire country, which spans only about 30° of longitude, making a single national timezone practical.
Tokyo is the world's most populous metropolitan area and a global financial powerhouse. The Tokyo Stock Exchange (TSE) opens at 09:00 JST and closes at 15:30 JST with a lunch break from 11:30 to 12:30 — one of the few major exchanges still observing a midday break. Tokyo's fixed UTC+9 means the trading day never shifts relative to the rest of the world's schedules: TSE always closes at 06:30 UTC, just as European morning trading begins. The lack of DST simplifies scheduling with Tokyo; you never need to check "is Japan currently on DST?" — it is always UTC+9.
Tokyo is 9 hours ahead of London (GMT), 14 hours ahead of New York (EST), and 17 hours ahead of Los Angeles (PST). This puts Tokyo so far ahead of the Americas that a live daytime meeting covering both is virtually impossible during normal business hours for either side. It is 1 hour ahead of Beijing and Seoul, and exactly the same offset as South Korea (KST) in winter. The JST zone also covers South Korea's Jeju island in practice, though Korea officially uses KST (also UTC+9).
London operates on Greenwich Mean Time (GMT, UTC+0) in winter and British Summer Time (BST, UTC+1) from late March to late October. The city sits at the Prime Meridian — longitude 0° — established at the Royal Observatory in Greenwich in 1884 when the International Meridian Conference adopted Greenwich as the world's reference point for time and longitude. The GMT standard was already in widespread use because of Britain's dominance in maritime navigation and the railway network, which demanded a single national time to replace the patchwork of local times that differed by minutes from town to town.
The UK introduced Daylight Saving Time during World War I in 1916, following Germany's lead, to reduce coal consumption by extending evening daylight. Today DST is governed by EU rules (retained in UK law post-Brexit), meaning the clocks change on the last Sunday of March and October. London is one of the world's most important financial centres: the London Stock Exchange opens at 08:00 GMT and closes at 16:30, overlapping with Asian market closes in the morning and US market opens in the afternoon — a position that helps make London the largest foreign-exchange trading centre on earth.
Because London is UTC+0 in winter, it serves as a natural reference point for international scheduling. A meeting at "noon UTC" is noon in London from November to March. The city is 5 hours ahead of New York (EST) in winter and 8 hours behind Tokyo (JST), making it the pivot of East–West business communication.
London is currently 8 hours behind Tokyo.
When it is 12:00 noon in Tokyo, it is 04:00 in London (based on current offsets — verify during DST transitions).
Tokyo does not observe DST — GMT+9 is used year-round. London observes DST, changing from GMT to GMT+1.