AST to Japan
+13hAST
ASTSOURCEJapan
JSTGreen rows indicate typical business hours (9 AM - 5 PM)
AST and JST on the World Map
The map below highlights the AST (Atlantic Standard Time) and JST (Japan Standard Time) timezone regions across the globe.
AST – Atlantic Standard Time
UTC-04:00Atlantic Standard Time (AST) is the time zone for the Canadian Atlantic provinces and the Caribbean, 4 hours behind UTC.
- •Puerto Rico uses AST year-round and does not observe DST.
- •AST is 1 hour ahead of EST.
- •Halifax, the capital of Nova Scotia, is the largest city in AST Canada.
JST – Japan Standard Time
UTC+09:00Japan Standard Time (JST) is the time zone for Japan, 9 hours ahead of UTC.
- •Japan does not observe daylight saving time.
- •Tokyo is the most populous metropolitan area in the world.
- •The Tokyo Stock Exchange operates from 9:00 AM to 3:00 PM JST.
- •JST is 14 hours ahead of EST and 9 hours ahead of GMT.
Time Conversion Guide: AST to Japan
AST runs on Atlantic Standard Time (AST) at UTC-04:00. Japan runs on Japan Standard Time (JST) at UTC+09:00. That puts AST 13 hours ahead of Japan — a difference of +13h at the current offsets.
In practice, when it is 9:00 AM in AST it is 10:00 PM in Japan. Midnight in AST is 1:00 PM in Japan. Neither zone observes daylight saving time, so the offset between them stays constant all year.
AST to Japan time conversion table
| AST (AST) | Japan (JST) | Day |
|---|---|---|
| 12:00 AM | 1:00 PM | same day |
| 6:00 AM | 7:00 PM | same day |
| 7:00 AM | 8:00 PM | same day |
| 8:00 AM | 9:00 PM | same day |
| 9:00 AM | 10:00 PM | same day |
| 12:00 PM | 1:00 AM | next day |
| 3:00 PM | 4:00 AM | next day |
| 5:00 PM | 6:00 AM | next day |
| 6:00 PM | 7:00 AM | next day |
| 9:00 PM | 10:00 AM | next day |
Why people convert AST to Japan time
- Scheduling a call from AST to Japan: a 10:00 AM start in AST lands at 11:00 PM in Japan, so you can confirm the slot without doing the arithmetic yourself.
- Handling a +13h gap: AST and Japan have no overlap inside a normal 9-to-5 day, so real-time meetings need an early-morning or late-evening slot on one side. 9:00 AM in Japan is 10:00 PM in AST.
- Watching a live event or market open: AST viewers need 10:00 PM in Japan to catch a 9:00 AM start there, and 11:00 AM if the event is anchored to AST.
- Always state the zone abbreviation, not just the hour. "3:00 PM AST" is unambiguous; "3 PM" across a +13h gap is not.
- With a +13h gap there is no shared 9-to-5 window, so alternate the early start: one week AST takes the early slot, the next week Japan does.
About AST (Atlantic Standard Time)
Atlantic Standard Time (AST) covers Canada's Atlantic provinces (Nova Scotia, New Brunswick, Prince Edward Island, and most of Labrador), as well as several Caribbean nations. Puerto Rico and the US Virgin Islands use AST year-round without daylight saving time. The Canadian provinces switch to Atlantic Daylight Time (ADT) in summer.
About JST (Japan Standard Time)
Japan Standard Time (JST) is the standard time zone for all of Japan. Japan does not observe daylight saving time. JST is 9 hours ahead of UTC and 14 hours ahead of EST. The Tokyo Stock Exchange, the world's third largest by market capitalization, operates on JST. South Korea uses the same offset (KST) but it is a distinct time zone.
Best time to call between AST and Japan
With a +13h offset there is no overlap inside a normal 9 AM – 5 PM day. Japan opens at 9:00 AM JST, which is 10:00 PM in AST, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
AST and Japan have no shared working hours because of the +13h gap. Teams need to alternate early starts or rely on asynchronous handovers.
AST is 13 hours ahead of Japan (AST UTC-04:00 → JST UTC+09:00). There is no shared 9-to-5 window, so plan around an early or late slot. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
AST
☀ Currently in DST
Standard: UTC-04:00 · DST: UTC-03:00
Clocks fall back on Sun, Nov 1, 2026
Japan
Does not observe DST
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between AST and Japan?
AST (AST, UTC-04:00) is 13 hours ahead of Japan (JST, UTC+09:00). The gap is currently +13h.
How do I convert AST time to Japan time?
Add +13h to AST local time. For example, 9:00 AM in AST is 10:00 PM in Japan.
What time is it in Japan right now?
Japan uses JST at UTC+09:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +13h offset from AST.
What is the best time to call Japan from AST?
There is no shared working-hours window because of the +13h gap. The closest option is 1:00 PM in AST, which is 2:00 AM in Japan.
Which is ahead, AST or Japan?
AST is 13 hours ahead of Japan. When it is 12:00 PM in AST it is 1:00 AM in Japan.
Do AST and Japan use different time zones?
AST uses AST at UTC-04:00, while Japan (Japan) uses JST at UTC+09:00. The IANA identifiers are America/Halifax and Asia/Tokyo.
Does daylight saving time affect the AST–Japan difference?
Neither zone observes daylight saving time, so the +13h offset between AST and Japan is fixed all year.
Which other cities share AST's time zone?
AST also covers Halifax, San Juan, Santo Domingo, Caracas, La Paz, Fredericton, Charlottetown.
Which countries use AST, AST's zone?
AST is used in Canada (Atlantic provinces), Puerto Rico, US Virgin Islands, Dominican Republic, Venezuela, Bolivia, Barbados, Trinidad and Tobago.
Is there a day difference between AST and Japan?
Sometimes. The +13h gap is large enough that 8:00 PM or later in AST already falls on the next day in Japan.
What is the time difference between AST and Japan?
Japan is +13h from AST.
What timezone is AST in?
AST operates on its local timezone.
What timezone is Japan in?
Japan operates on its local timezone.
Which countries use AST (Atlantic Standard Time)?
AST is used in Canada (Atlantic provinces), Puerto Rico, US Virgin Islands, Dominican Republic, Venezuela, Bolivia, and 2 more countries.
Does AST observe daylight saving time?
Yes, AST switches to ADT during summer months.
What are some interesting facts about AST?
Puerto Rico uses AST year-round and does not observe DST. AST is 1 hour ahead of EST.
Which cities are in the JST timezone?
Major cities in the JST timezone include Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka.
What is the UTC offset for JST?
Japan Standard Time (JST) is at UTC+09:00.
What should I know about the JST timezone?
Japan does not observe daylight saving time. Tokyo is the most populous metropolitan area in the world.
When is it midnight in AST, what time is it in Japan?
When it is 12:00 AM (midnight) in AST (AST), it is +13h later in Japan (JST).
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See every conversion from AST →·See every conversion from Japan →