Timezone details
- Identifier
- Abbreviation
- —
- Transitioned
- May 30, 2021 at 09:00 PM
- Featured city
- Road Town
America • Tortola
British Virgin IslandsCurrent local time
00:16:13
Sunday, May 31, 2026
UTC offset
UTC-04:00
Tortola does not observe daylight saving time. Clocks stay on UTC-04:00 all year long.
Atlantic Standard Time (AST)
Atlantic Standard Time (AST) stretches across 29 zones spanning the East Coast of North America and parts of the Caribbean Sea, popular for keeping things simple: most jurisdictions, such as Anguilla and Antigua and Barbuda, stay locked to four hours behind UTC all year. Just across the line in Canada and a few other areas, a handful of communities spring forward in summer, so if you’re coordinating workflows with government teams or customers in AST, it’s worth confirming whether their specific zone keeps the same offset every month.\n\nAST has a fascinating geographic spread: zones like Blanc-Sablon and Glace_Bay in Canada regularly join daylight saving and stay an hour ahead from March to November, making them closer to Newfoundland Time; while other zones in the Caribbean hold steady.
No. Most Caribbean territories—Anguilla, Antigua, Aruba, Barbados, Curaçao, and Dominica—stay on AST permanently. However, six Canadian and Atlantic-coast communities (for example America/Blanc-Sablon and America/Glace_Bay) spring forward to UTC-03:00 during the northern hemisphere’s DST window.
The four-hour offset is the year-round baseline. When a member zone observes DST, clocks shift one hour forward—so AST becomes UTC-03:00 for those months. The UI tables above show the exact status for each zone.
They overlap but aren’t identical. Eastern Standard Time is also UTC-05:00 standard / UTC-04:00 daylight, while Caribbean zones like AST typically don’t observe any changes—making AST a more predictable choice for regional calendars.
Public records list Anguilla, Antigua and Barbuda, Aruba, Barbados, Curaçao, and Dominica as the current ‘no-shift’ members—all holding the -04:00 offset permanently, so your scheduled calls won’t jump mid-year.
Blanc-Sablon is one of the few AST-labeled zones that fully adopts Canada’s daylight schedule. From late March onward, it switches to UTC-03:00 to match Atlantic Daylight Time, before stepping back to -04:00 in early November.
Historically, the Atlantic Time label linked maritime provinces to Caribbean trading partners that preferred a fixed 240 minute gap from UTC. Over the 20th century, various island governments chose not to shift their clocks while neighborly Canadian zones did, creating the mix we see today.
Use region-level identifiers rather than common abbreviations. Write ‘America/Glace_Bay’ or ‘America/Curacao’ in every invite—this avoids the one-letter difference between AST standard and AST-summer-time and prevents double-bookings.
No. All six Caribbean jurisdictions mandated permanent Atlantic Standard Time after World War II. Today, AST clocks in the Caribbean never move, making them ideal anchors for cross-border meetings.
Aviation and maritime systems commonly use UTC-based references (Zulu time) and post a time-zone alias for cabin announcements. So even when Blanc-Slabon springs to -5 EDT, traffic control still publishes its plain offsets.