Guam Time Zone
There are two names and corresponding abbreviations that are in common use for Guam’s time zone.
• Chamorro Standard Time (ChST) — The current official name and abbreviation.
• Guam Standard Time (GST) — The former official name and abbreviation.
Guam observes the same time all year. So, there is no Daylight Saving Time (DST) on Guam, and the clocks remain the same year round.
Always Same Time
UTC+10 Standard Time (all year round)
Northern Mariana Islands (all)
Federated States of Micronesia (western part)
Russia (see below)
- Vladivostok Time
- Far Eastern Federal District; Jewish Autonomous Oblast, Khabarovsk Krai, Primorsky Krai and Sakha Republic (central part; east of 140 degrees longitude and including the Abyysky, Allaikhovsky, Momsky, Nizhnekolymsky, and Srednekolymsky districts)
Papua New Guinea (Except Autonomous Region of Bougainville)
Australia (see below)
- Queensland is UTC+10:00 (year round). Queensland is the only Eastern Australian territory that doesn’t observe Daylight Saving Time (DST). So it’s the same time as Guam year round.
Antarctica (some bases)
Major cities that are always the same time as Guam
Port Moresby, Papua New Guinea
Australian Eastern Standard Time (AEST)
- New South Wales — Standard UTC+10:00 / (DST) UTC+11:00
- Victoria — Standard UTC+10:00 / (DST) UTC+11:00
- Tasmania — Standard UTC+10:00 / (DST) UTC+11:00
- Australian Capital Territory — Standard UTC+10:00 / (DST) UTC+11:00
Always 30 Minutes Before or After Guam
South Australia and New South Wales – Yancowinna are not in UTC+10:00, but they switch back and forth between UTC+09:30 and UTC+10:30. Making it so it’s always either 30 minutes earlier, or 30 minutes later than Guam.