Tokyo is 8 hours ahead in January. By July, the gap shrinks to 7. Book the call for 08:00 Brussels time and you catch Tokyo at 15:00 in summer or 16:00 in the cold months. Wait until 10:00 Brussels and you hit 17:00 or 18:00, the very edge of the Tokyo workday. Anything later is a voicemail.

Brussels vs Tokyo: 7 or 8 hours behind

Tokyo stays ahead. Always.

Brussels runs on CEST (UTC+2) from the last Sunday of March to the last Sunday of October. In that stretch, Tokyo is 7 hours ahead. The rest of the year, Brussels is on CET (UTC+1) and Tokyo pulls 8 hours ahead.

On 15 July, 09:00 in Brussels is 16:00 in Tokyo. On 15 January, 09:00 in Brussels is 17:00 in Tokyo.

Brussels vs Singapore: 6 or 7 hours behind

Singapore does not move. Its offset sits at UTC+8 all year. The only clock that shifts is the one in Brussels.

In summer, Singapore is 6 hours ahead. In winter, 7.

Call Brussels at 10:00 in summer and it is 16:00 in Singapore. Same 10:00 in winter, and Singapore reads 17:00.

Brussels vs Dubai: 2 or 3 hours behind

Dubai is fixed at UTC+4. No daylight saving, no clock changes. The entire difference swings on what Brussels does.

In summer, Dubai is 2 hours ahead. In winter, 3.

On 15 July, 09:00 in Brussels is 11:00 in Dubai. On 15 January, 09:00 in Brussels is 12:00 in Dubai.

Best meeting window: Brussels to Tokyo

Book 08:00 to 10:00 Brussels time.

That gives you 15:00 to 17:00 Tokyo in summer, or 16:00 to 18:00 in winter. Brussels offices open around 09:00 and are fully staffed by 10:00. Tokyo’s workday ends between 17:00 and 18:00. An 08:00 Brussels start catches the tail of the Tokyo afternoon. A 10:00 start catches the evening wrap-up.

Skip the Brussels afternoon. At 15:00 Brussels, it is 22:00 Tokyo in summer. 23:00 in winter. Nobody answers.

Best meeting window: Brussels to Singapore

Book 09:00 to 11:00 Brussels time.

That lands at 15:00 to 17:00 Singapore in summer, or 16:00 to 18:00 in winter. Singapore’s business day runs 09:00 to 18:00. A 09:00 Brussels start hits 15:00 Singapore, solidly inside working hours. An 11:00 start hits 17:00 in summer, 18:00 in winter. In winter, 18:00 is the hard stop.

Do not call at 14:00 Brussels. That is 20:00 Singapore in summer, 21:00 in winter. After hours. Unless you have a pre-arranged evening slot, do not do it.

Best meeting window: Brussels to Dubai

Book 10:00 to 12:00 Brussels time in winter.

That gives you 13:00 to 15:00 Dubai. Dubai’s workday often starts at 09:00 and runs through 13:00, breaks for lunch and prayer, then resumes 16:00 to 18:00. A 10:00 Brussels call hits the end of the morning block. A 12:00 call hits 15:00 Dubai, right inside the afternoon block.

In summer, shift the window. Book 11:00 to 12:00 Brussels. A 10:00 Brussels call in summer lands at 12:00 Dubai, which falls squarely in the lunch and prayer gap. An 11:00 start gives 13:00 Dubai, still inside the morning block before the break ends.

Do not call early. At 08:00 Brussels, it is 10:00 Dubai in summer. Someone just arrived at work. The 10:00 to 12:00 slot is safer year-round, but in summer, use the upper end.

DST impact on Asia calls: summer vs the colder months

Brussels moves to CEST on the last Sunday of March. In 2026, that is 29 March. Clocks go forward at 02:00 local time. Brussels becomes UTC+2. The gap with Tokyo drops from 8 hours to 7. With Singapore, 7 to 6. With Dubai, 3 to 2.

Brussels moves back to CET on the last Sunday of October. In 2026, that is 25 October. Clocks go back at 03:00 local time. Brussels becomes UTC+1. All gaps widen by one hour.

The transition weeks are dangerous. A recurring meeting set for 09:00 Brussels on the last Friday of October lands at a different hour in Asia the following Monday. Check it. Do not trust the calendar app.