London to Sydney is one of the world's most extreme time-zone pairings — and one of the trickiest, because the gap actually changes four times a year. It ranges from 9 to 11 hours depending on which cities are on daylight saving time. If you coordinate with Australia regularly, understanding this is essential.
How the Time Difference Works
Sydney is in Australian Eastern Time and observes DST from October to April. London is in GMT/BST and observes DST from late March to late October. Because the southern hemisphere seasons are flipped, the two cities' DST periods only partially overlap — creating a yearly pattern where the gap is 11 hours, 10 hours, 9 hours, then 10 hours again.
London
Sydney
Business Hours Overlap
The table below shows when typical business hours (9 AM – 6 PM) in each city overlap. Times shown are London time, with the corresponding Sydney time in brackets.
| London | Sydney | Meeting quality |
|---|---|---|
| 8:00 AM | 6:00 PM | ~ OK |
| 9:00 AM | 7:00 PM | ~ OK |
| 10:00 AM | 8:00 PM | ~ OK |
| 11:00 AM | 9:00 PM | Off hours |
| 12:00 PM | 10:00 PM | Off hours |
| 1:00 PM | 11:00 PM | Off hours |
| 2:00 PM | 12:00 AM (next day) | Off hours |
| 3:00 PM | 1:00 AM (next day) | Off hours |
| 4:00 PM | 2:00 AM (next day) | Off hours |
| 5:00 PM | 3:00 AM (next day) | Off hours |
| 6:00 PM | 4:00 AM (next day) | Off hours |
⏰ Best time to call
7:00 AM to 9:00 AM London — this lands during Sydney afternoon, a productive time for both sides. Alternative: 6:00 PM to 8:00 PM Sydney for early-day calls on the Sydney side.
DST — The Detail Most People Get Wrong
Both London and Sydney observe daylight saving time, but they switch on slightly different dates. For roughly two to three weeks each spring and autumn, the usual time gap is briefly off by one hour. If you're scheduling a recurring meeting or a flight, double-check the exact dates around mid-March and late October.