London vs Tokyo: Time Difference, Business Hours, and Best Meeting Times

Time Zone Basics: GMT/BST vs JST

London operates on Greenwich Mean Time (GMT) during winter and British Summer Time (BST) during summer daylight saving months. Tokyo uses Japan Standard Time (JST) all year, with no daylight saving adjustments. The standard offset for JST is UTC+9. London's time zone history shows it has used GMT for most of the year, shifting to BST (UTC+1) from late March to late October.

Currently (as of January 2026, winter), London is on GMT (UTC+0), making it 9 hours behind Tokyo. For example, when it's 12:00 noon in London, it is 21:00 (9 PM) in Tokyo. When London switches to BST at the end of March 2026, the difference becomes 8 hours (London UTC+1, Tokyo UTC+9).

How Daylight Saving Time Affects the Difference

The daylight saving schedule in London (BST) runs from the last Sunday in March to the last Sunday in October. During this period, London is UTC+1, so the offset narrows to 8 hours. The rest of the year, London is on GMT (UTC+0), yielding a 9-hour gap. Tokyo does not observe DST, so the change is entirely driven by London's clock shift. This means that meetings planned during the summer months have a slightly more favorable overlap for London-based workers, as Tokyo's business hours align one hour earlier relative to London.

Business Hours Overlap: When to Call or Meet

Standard business hours in both cities are roughly 9:00 AM to 5:00 PM local time. However, Tokyo often starts earlier (some offices at 8:00 AM) and may extend into evening, while London tends to stick closer to 9–5. The key overlap occurs when London's afternoon meets Tokyo's late afternoon/early evening.

As the table shows, the overlap is longer during BST (summer) because London time is one hour closer to Tokyo. In winter, only a 3-hour window exISTs (London morning = Tokyo evening). For meetings, aim for London late morning or early afternoon to catch Tokyo before they leave work.

Best Meeting Times Across the Two Cities

To maximize participation, consider these recommended slots:

• During GMT (winter): 9:00 AM – 12:00 PM London (6:00 PM – 9:00 PM Tokyo). This is Tokyo's post-dinner or late-evening window; suitable for informal calls but not ideal for all.
• During BST (summer): 9:00 AM – 2:00 PM London (5:00 PM – 10:00 PM Tokyo). This offers a wider window and aligns with Tokyo's pre-closing or overtime hours.
• Reverse (Tokyo afternoon to London morning): 9:00 AM – 5:00 PM Tokyo = 12:00 AM – 8:00 AM London (midnight to 8 AM) – impractical for London, so avoid.

For consistent weekly meetings, consider alternating times: one week London early morning (9 AM London = 6 PM Tokyo winter), the next week London late afternoon (4 PM London = 1 AM Tokyo next day) – but the latter is tough for Tokyo. The best compromise is to meet at around 10:00 AM London (7 PM Tokyo winter, 6 PM Tokyo summer) – that gives London a start and Tokyo just before or after dinner.

Practical Tips for Scheduling

Remember that London's clock changes occur at 1:00 AM GMT (switch to BST) and 2:00 AM BST (back to GMT). These happen on Sundays, so the impact on workdays is gradual. Always confirm current offset using a reliable tool like the London time homepage. Also, note that Tokyo has no DST, so the only shift is London's.

If you frequently collaborate with Tokyo, it's helpful to keep a dual timer set. For instance, during winter, set a reminder for 10:00 AM London (7:00 PM Tokyo) – a good midpoint. During summer, 10:00 AM London is 6:00 PM Tokyo – still workable. Avoid scheduling after 2:00 PM London in summer (after 10 PM Tokyo) unless agreed.

Time Conversion Examples

Here are common conversion pairs:

• London 8:00 AM (GMT) → Tokyo 5:00 PM (Tokyo end of day)
• London 12:00 PM (GMT) → Tokyo 9:00 PM (Tokyo evening)
• London 3:00 PM (GMT) → Tokyo 12:00 AM (midnight) – no overlap
• London 9:00 AM (BST) → Tokyo 5:00 PM (Tokyo end of day)
• London 1:00 PM (BST) → Tokyo 9:00 PM (Tokyo evening)

When planning, use the current offset. For reference, visit London business hours guide for standard working times, and check the sunrise and sunset page for daylight availability in London.

Frequently Asked Questions

Common queries about the London–Tokyo time difference:

• How many hours ahead is Tokyo than London? Tokyo is 8 or 9 hours ahead, depending on London DST.
• Do the clocks change in Tokyo? No, Japan does not observe daylight saving time.
• What is the best time to call Tokyo from London? Between 9:00 AM and 12:00 PM London (winter) or 9:00 AM to 2:00 PM London (summer).
• Is there a time difference at all on the day London springs forward? On the day of the switch (typically last Sunday in March), London jumps from GMT to BST at 1:00 AM local time, so the difference changes from 9 hours to 8 hours at that moment.

For more answers, see our London Time FAQ page.