Best Time to Call Japan from the UK
Japan Standard Time is 8 hours ahead of UK time during British Summer Time (late March to late October) and 9 hours ahead in winter. The gap is significant -- when London starts its workday at 9 AM, Tokyo is already at 5:00 PM in summer or 6:00 PM in winter and wrapping up. This guide helps you find the best calling windows between the UK and Japan.
Time Difference Overview
Japan does not observe Daylight Saving Time. JST stays at UTC+9 year-round. The UK, however, switches between GMT (winter) and BST (summer). This means the UK-Japan time difference changes when the UK clocks shift.
UK time (GMT/BST)
London, Edinburgh, Dublin
Japan Standard Time (JST)
Tokyo, Osaka, Yokohama
Winter (GMT): The UK is at UTC±0, making the gap 9 hours. An 8:00 AM London meeting lands at 5:00 PM in Tokyo.
Summer (BST): The UK shifts to UTC+1, shrinking the gap to 8 hours. An 8:00 AM London meeting lands at 4:00 PM in Tokyo -- one hour earlier for Japan.
Work Hours Overlap
Visual timeline showing 9 AM -- 6 PM work hours for the UK and Japan, with overlap highlighted.
These times apply on all dates in 2026–2027 except:
- Jan 1 – Mar 28, 2026; Oct 25, 2026 – Mar 27, 2027; Oct 31 – Dec 31, 2027: Tokyo times are 1 hour later.
The overlap between standard UK and Japan business hours is extremely narrow. The UK morning (8–10 AM) corresponds to 4–6 PM in Tokyo during British Summer Time and 5–7 PM in winter. This makes early morning UK calls the primary option.
GMT/BST to JST Conversion Table
Full 24-hour comparison. Business hours (9 AM -- 6 PM) are highlighted.
| London (GMT/BST) | Tokyo (JST) |
|---|---|
| 12:00 AM | 8:00 AM |
| 1:00 AM | 9:00 AM |
| 2:00 AM | 10:00 AM |
| 3:00 AM | 11:00 AM |
| 4:00 AM | 12:00 PM |
| 5:00 AM | 1:00 PM |
| 6:00 AM | 2:00 PM |
| 7:00 AM | 3:00 PM |
| 8:00 AM | 4:00 PM |
| 9:00 AM | 5:00 PM |
| 10:00 AM | 6:00 PM |
| 11:00 AM | 7:00 PM |
| 12:00 PM | 8:00 PM |
| 1:00 PM | 9:00 PM |
| 2:00 PM | 10:00 PM |
| 3:00 PM | 11:00 PM |
| 4:00 PM | 12:00 AM +1 day |
| 5:00 PM | 1:00 AM +1 day |
| 6:00 PM | 2:00 AM +1 day |
| 7:00 PM | 3:00 AM +1 day |
| 8:00 PM | 4:00 AM +1 day |
| 9:00 PM | 5:00 AM +1 day |
| 10:00 PM | 6:00 AM +1 day |
| 11:00 PM | 7:00 AM +1 day |
These times apply on all dates in 2026–2027 except:
- Jan 1 – Mar 28, 2026; Oct 25, 2026 – Mar 27, 2027; Oct 31 – Dec 31, 2027: Tokyo times are 1 hour later.
Best Meeting Times
Top ranked time slots for a 1-hour UK -- Japan meeting with standard 9 AM -- 6 PM work hours.
All members within working hours. 1 in mid-day range (9 AM–5 PM).
1 of 2 members within working hours. 1 in mid-day range (9 AM–5 PM). Outside work hours for Japan.
1 of 2 members within working hours. 1 in mid-day range (9 AM–5 PM). Outside work hours for Japan.
1 of 2 members within working hours. 1 in mid-day range (9 AM–5 PM). Outside work hours for Japan.
1 of 2 members within working hours. 1 in mid-day range (9 AM–5 PM). Outside work hours for UK.
These times apply on all dates in 2026–2027 except:
- Jan 1 – Mar 28, 2026; Oct 25, 2026 – Mar 27, 2027; Oct 31 – Dec 31, 2027: Tokyo times are 1 hour later.
Practical Tips for UK-Japan Scheduling
A gap of 8 hours in UK summer and 9 hours in UK winter makes synchronous overlap challenging. These strategies help UK-Japan teams stay connected without burning out either side.
- Target 8:00 AM -- 9:00 AM UK time. This maps to 5:00 PM -- 6:00 PM in Tokyo (or 4:00 PM -- 5:00 PM during UK summer). It is the only window where both sides are within or near standard business hours. For the UK, it means starting early; for Japan, it means staying until end of day.
- Consider a "Japan morning / UK evening" slot for alternation. If your team meets twice a week, alternate between a UK morning call (8 AM in London / 5 PM in Tokyo in winter, 4 PM in summer) and a Japan morning call (9 AM in Tokyo / 12 AM in London in winter, 1 AM in summer). The Japan morning option is tough for the UK, so reserve it for important discussions that benefit Japan-side participants and keep it infrequent.
- Leverage the UK summer advantage. During British Summer Time (late March to late October), the UK moves to UTC+1, reducing the gap from 9 hours to 8 hours. An 8:00 AM meeting in London is 4:00 PM in Tokyo instead of 5:00 PM -- giving Japan an earlier finish. Plan heavier collaboration schedules during UK summer months.
- Keep meetings short and focused. With limited overlap, every minute counts. Set clear agendas, share materials in advance, and use the synchronous time strictly for decisions that require real-time discussion.
- Build an asynchronous handoff workflow. Structure your team's day so Japan works on tasks and hands off with detailed notes before they leave. UK picks up those notes when they start their day and completes their handoff before Japan's next morning. This "follow the sun" pattern maximizes the time difference rather than fighting it.
- Watch for the UK DST transition dates. The table in the next section lists them. Japan does not observe DST, so the meeting time will shift by one hour for the Japan side whenever the UK clocks change. Send a reminder to all participants a week before each transition.
How UK DST Affects Japan Calls
Japan does not observe Daylight Saving Time. When the UK clocks shift, the gap between London and Tokyo changes:
Winter (GMT: UTC±0)
Late October -- March
- Gap 9 hours
- 8:00 AM in London 5:00 PM in Tokyo
Summer (BST: UTC+1)
March -- October
- Gap 8 hours
- 8:00 AM in London 4:00 PM in Tokyo
| Dates | London | Tokyo | Difference |
|---|---|---|---|
| Jan 1 – Mar 28, 2026 | UTC±0 | UTC+9 | +9h |
| Mar 29 – Oct 24, 2026 | UTC+1 | UTC+9 | +8h |
| Oct 25, 2026 – Mar 27, 2027 | UTC±0 | UTC+9 | +9h |
| Mar 28 – Oct 30, 2027 | UTC+1 | UTC+9 | +8h |
| Oct 31 – Dec 31, 2027 | UTC±0 | UTC+9 | +9h |
Tokyo does not use daylight saving time.
UK summer time actually improves the overlap slightly. Use calendar apps with IANA time zones (Europe/London, Asia/Tokyo) so recurring meetings adjust automatically.
Related Resources
- Meeting Planner -- Find the best overlap window with custom work hours for your specific team.
- Best Time to Call India from the US -- Scheduling guide for the US-India corridor.
- Best Time to Call Europe from the US -- Scheduling guide for the US-Europe corridor.
- Scheduling Across Time Zones -- Best practices for fairness and reducing late-night calls.