A calendar entry for 10:00 in Brussels lands at 17:00 in Tokyo from late March to late October, and 18:00 from late October to late March. The difference is never fixed. Assume the gap stays the same year-round and you will miss your window.
Why the Brussels, Tokyo gap jumps from 7 to 8 hours
In Brussels summer (Central European Summer Time, UTC+2), Tokyo runs 7 hours ahead. When Brussels switches back to Central European Time (UTC+1), the gap grows to 8 hours.
Here is the shift across the year:
| Brussels date range | Brussels time zone | UTC offset | Tokyo offset | Time difference |
|---|---|---|---|---|
| Late October to late March | CET (winter) | UTC+1 | UTC+9 | +8 hours |
| Late March to late October | CEST (summer) | UTC+2 | UTC+9 | +7 hours |
On 15 January 2026, Brussels is on winter time. 09:00 in Brussels is 17:00 in Tokyo. On 15 July 2026, Brussels is on summer time. 09:00 in Brussels is 16:00 in Tokyo.
The change happens on specific dates. In 2026, Brussels moves to summer time on Sunday 29 March at 02:00 local time (clocks go forward to 03:00). It moves back to winter time on Sunday 25 October at 03:00 local (clocks go back to 02:00). The gap shifts by one hour overnight on those Sundays.
Japan’s fixed clock makes the Brussels gap a moving target
Japan has not observed daylight saving time since 1952. The country stays on Japan Standard Time (UTC+9) all year. Brussels moves. Tokyo does not.
When Brussels springs forward, the gap narrows by one hour. When Brussels falls back, the gap widens by one hour.
A recurring meeting needs two adjustments a year. Skip the adjustment and you dial in an hour early or late.
Best calling windows from Brussels to Tokyo
No overlap exists between a normal working day in Brussels and a normal working day in Tokyo. A typical Brussels business day runs 09:00 to 17:00. A typical Tokyo business day runs 09:00 to 17:00 Japan Standard Time.
When Brussels is on summer time (+7 hours), 09:00 in Brussels is 16:00 in Tokyo. That gives you one hour of overlap at the end of Tokyo’s day. When Brussels is on winter time (+8 hours), 09:00 in Brussels is 17:00 in Tokyo. The overlap is zero.
The best windows work in one direction:
Calling Tokyo from Brussels
Dial between 09:00 and 10:00 Brussels time. That reaches Tokyo between 16:00 and 17:00 in summer, or 17:00 and 18:00 in winter. You catch the tail of Tokyo’s business day. Any later and Tokyo has gone home.
Calling Brussels from Tokyo
Dial between 14:00 and 17:00 Tokyo time. That reaches Brussels between 07:00 and 10:00 in summer, or 06:00 and 09:00 in winter. The sweet spot is Tokyo 16:00 to 17:00. It lands in Brussels at 09:00 to 10:00 in summer, the start of the Brussels day.
Avoid a midday call. Tokyo at 12:00 puts Brussels at 04:00 or 05:00. Nobody answers.
Zero market overlap between Brussels and Tokyo
Euronext Brussels trades 09:00 to 17:30. The Tokyo Stock Exchange runs 09:00 to 15:00 (cash equity), with a morning session 09:00 to 11:30 and an afternoon session 12:30 to 15:00 Japan Standard Time. No overlap exists. When Brussels opens, Tokyo has already closed. When Tokyo opens, Brussels is asleep.
Trading or settling across these markets means you cannot execute in real time. Orders placed in one market fill after the other opens. That is a structural constraint, not a scheduling problem.
For project teams, split the strategy by role. Developers who need synchronous work should push for a late Brussels morning window. Managers who only need daily status can use email and async tools. Skip the weekly one-hour video call for a large group. Break it into two shorter calls, one for each side’s morning, or record a briefing for the other time zone.
The best time to call Brussels from Tokyo page has a full breakdown of windows for different roles. The Brussels financial markets hours page explains the specific trading overlap with Asia. Use the time zone converter to check the exact difference on any date.