Brisbane is the same time as Sydney in winter, but 1 hour behind in summer. Queensland doesn't observe DST, while NSW does. From October-April when Sydney is on AEDT, Brisbane (AEST) is 1 hour behind. In winter, they're the same.
This DST difference causes confusion for cross-state business during summer months.
Check the season! In winter, no conversion needed. In summer, 9 AM Brisbane = 10 AM Sydney. Business hours still overlap well year-round.
Brisbane and Sydney are connected by frequent flights taking about 1.5 hours. Qantas, Virgin Australia, and Jetstar operate 40+ daily flights.