London vs Tokyo: The Current Time Difference
Japan runs on Japan Standard Time (JST), a fixed UTC+9, year round. London toggles between GMT (UTC+0) in winter and British Summer Time (BST, UTC+1) in summer. The gap:
- Winter (GMT, late October to late March): London is 9 hours behind Tokyo.
- Summer (BST, late March to late October): London is 8 hours behind Tokyo.
The 2026 switch dates: clocks spring forward on 29 March and fall back on 25 October. In those transition weeks, the difference shifts overnight.
GMT/BST vs JST: Why Japan Has No Daylight Saving
Japan abandoned daylight saving in 1952 and has held JST at UTC+9 ever since. The only moving part in the London, Tokyo equation is London’s seasonal switch.
| Season | London offset | Tokyo offset | Difference |
|---|---|---|---|
| Winter (GMT) | UTC+0 | UTC+9 | London 9 hours behind |
| Summer (BST) | UTC+1 | UTC+9 | London 8 hours behind |
A recurring weekly call needs two adjustments a year, one in March and one in October. Miss one and you show up an hour early or late.
The Early Morning Window for Business
The sole block where standard hours intersect is early morning London time. 07:00-09:00 in London catches 15:00-17:00 in Tokyo. London’s typical 09:00-17:00 day ends at 01:00-02:00 Tokyo time. Tokyo’s 09:00-17:00 starts at midnight London time.
What to do: Pin calls at 07:30 or 08:00 London time. That gives you 15:30 or 16:00 in Tokyo, late enough that the post-lunch slump has passed, early enough before the evening rush.
What to skip: A London 14:00 meeting. That is 22:00 (summer) or 23:00 (winter) in Tokyo. Unless your counterpart keeps vampire hours, nobody answers.
Eastbound Travel and Jet Lag
Flying London to Tokyo crosses 8 or 9 time zones eastbound, producing phase-advance jet lag. Your body clock lurches forward; you feel drowsy while Tokyo is still sunlit.
Most flights depart London late morning or early afternoon and touch down in Tokyo late afternoon. If you sleep on the plane, you wake into Tokyo’s evening. Stay awake until at least 21:00 local time. Crash before 20:00 and you will be wide awake at 03:00.
Quick Reference: Time Difference by Season
| London time | Summer (BST, UTC+1) → Tokyo | Winter (GMT, UTC+0) → Tokyo |
|---|---|---|
| 06:00 | 14:00 | 15:00 |
| 07:00 | 15:00 | 16:00 |
| 08:00 | 16:00 | 17:00 |
| 09:00 | 17:00 | 18:00 |
| 10:00 | 18:00 | 19:00 |
| 12:00 | 20:00 | 21:00 |
| 15:00 | 23:00 | 00:00 (next day) |
| 17:00 | 01:00 (next day) | 02:00 (next day) |
Rule of thumb: Summer, add 8 hours. Winter, add 9 hours. In the fortnight after the March change and before the October change, double-check.
Who Should Ignore the Default Advice
The standard play is to use the 07:00-09:00 London window for calls. That works for a London manager dialling a Tokyo team. If you are a Tokyo-based employee reporting to a London boss, flip it: your end of the window is 15:00-17:00 JST. Block that slot as “London window” and refuse internal meetings that run past 16:30. Your boss will not reschedule their morning for you.
If you are a freelancer or consultant who can shift your day, try starting at 06:00 London time (14:00 Tokyo) and finishing at 14:00 (22:00 Tokyo). That delivers a full stretch of shared hours with Tokyo’s afternoon and partial coverage of London’s morning.