What Time Zone Is Guam In?
Guam uses a single timezone: the primary designation is Australia/Sydney, which is currently UTC+11:00 from Coordinated Universal Time. The IANA Time Zone Database , the authoritative global reference used by operating systems, web services, and programming languages worldwide, lists this as Australia/Sydney.
Regional Context
Micronesia's island nations cluster around UTC+10:00 to UTC+12:00. The Federated States of Micronesia (FSM) uses two zones: Pohnpei/Kosrae (UTC+11:00) and Chuuk/Yap (UTC+10:00). Palau uses UTC+09:00 permanently. Guam and the Northern Mariana Islands (US territories) observe ChST (Chamorro Standard Time, UTC+10:00) permanently with no DST. Marshall Islands use UTC+12:00. Nauru uses UTC+12:00. Kiribati's easternmost islands (Line Islands, including Kiribati Christmas Island) use UTC+14:00, the furthest forward timezone from UTC, 26 hours ahead of American Samoa (UTC-12:00).
Current Time in Hagåtña
The capital city Hagåtña observes the Australia/Sydney timezone, currently at UTC+11:00. The live clock above updates every second using your browser's Intl.DateTimeFormat API with the IANA zone identifier. To convert Hagåtña time to UTC, subtract the offset shown: Hagåtña's local time minus 11:00 hours equals UTC.
Daylight Saving Time in Guam
The DST status for Guam is shown in the indicator above. When DST is in effect, clocks advance by one hour, temporarily shifting Guam's UTC offset by +1. Countries that do not observe DST, including Japan, China, India, and most of Africa, maintain a fixed offset year-round. The IANA Time Zone Database contains the complete historical record of DST transitions for Australia/Sydney, including past rule changes and future scheduled transitions.
Scheduling Calls With Guam
When arranging calls or meetings with contacts in Guam, standard business hours run 09:00 to 18:00 local time (Australia/Sydney). In UTC, that window is 22:45 to 07:45 UTC. The time difference tool on this site calculates the overlap between any two cities' business hours, so you can find the shared window without mental arithmetic. If you're in a different country, visit the time difference page for your city vs. Hagåtñafor a full hour-by-hour breakdown.
Timezone Abbreviation for Guam
The GMT+11 abbreviation appears on airline tickets, broadcast schedules, and financial contracts when referencing Guam time. Timezone abbreviations are not globally unique, IST, for example, can mean India Standard Time (UTC+05:30), Irish Standard Time (UTC+01:00), or Israel Standard Time (UTC+02:00). The IANA identifier Australia/Sydney is unambiguous: it maps to exactly one timezone in the world. When writing times for a global audience, always include both the abbreviation and the UTC offset to prevent misreading. The IANA Time Zone Database records every past and future rule change for Australia/Sydney, making it the only reliable reference for historical time conversions.
Calling Guam from Abroad
International callers reach Guam using the code +1671. Standard business hours run 09:00 to 18:00 local (Australia/Sydney), which in UTC is 22:45 to 07:45 UTC. The best window for international calls is 10:00 to 16:00 Guam local time, after the morning rush and before post-17:00 wind-down. Mobile coverage in Hagåtña follows local carrier standards. International roaming calls to Guam are billed at the caller's international rate, not the local Guam rate.
Currency and Banking Hours in Guam
Domestic banks in Hagåtña operate on Australia/Sydney time. Wire transfers, invoice settlements, and currency conversions must typically be initiated before 17:00 Guam local time to be processed same-day. The forex market trades 24 hours, but domestic banking settlement in Guam follows Australia/Sydney business hours. When sending international transfers to Guam, factor in the UTC offset (UTC+11:00) to ensure your instruction arrives before the local cut-off time. Same-day settlement typically requires initiation before 04:45 UTC.
Guam: A Single-Zone Country
Guam observes a single timezone nationwide: Australia/Sydney (UTC+11:00). Single-zone countries have a scheduling advantage, there is no ambiguity about which zone a meeting time refers to, and businesses across the country share the same clock. This simplifies domestic commerce, broadcast scheduling, and government coordination.