Osaka to ACST
+0h 30mOsaka
JSTSOURCEACST
ACSTGreen rows indicate typical business hours (9 AM - 5 PM)
JST and ACST on the World Map
The map below highlights the JST (Japan Standard Time) and ACST (Australian Central Standard Time) timezone regions across the globe.
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.
ACST – Australian Central Standard Time
UTC+09:30Australian Central Standard Time (ACST, UTC+09:30) covers South Australia and the Northern Territory, on a half-hour offset.
- •ACST uses a half-hour offset: UTC+09:30.
- •South Australia moves to ACDT (UTC+10:30) in summer; the Northern Territory does not.
- •Adelaide and Darwin are 30 minutes apart during daylight saving, level in winter.
- •Adelaide is one of the few major cities on a 30-minute offset.
About Osaka
WikipediaOsaka operates on Japan Standard Time (JST), UTC+9. As Japan's second economic center and a manufacturing hub, Osaka shares business hours with Tokyo.
Osaka Castle was originally built in 1583 and has been rebuilt several times.
Understanding the +0h 30m Gap: Osaka vs ACST
Osaka runs on Japan Standard Time (JST) at UTC+09:00. ACST runs on Australian Central Standard Time (ACST) at UTC+09:30. That puts Osaka 30 minutes ahead of ACST — a difference of +0h 30m at the current offsets.
In practice, when it is 9:00 AM in Osaka it is 9:30 AM in ACST. Midnight in Osaka is 12:30 AM in ACST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Osaka to ACST time conversion table
| Osaka (JST) | ACST (ACST) | Day |
|---|---|---|
| 12:00 AM | 12:30 AM | same day |
| 6:00 AM | 6:30 AM | same day |
| 7:00 AM | 7:30 AM | same day |
| 8:00 AM | 8:30 AM | same day |
| 9:00 AM | 9:30 AM | same day |
| 12:00 PM | 12:30 PM | same day |
| 3:00 PM | 3:30 PM | same day |
| 5:00 PM | 5:30 PM | same day |
| 6:00 PM | 6:30 PM | same day |
| 9:00 PM | 9:30 PM | same day |
Why people convert Osaka to ACST time
- Scheduling a call from Osaka to ACST: a 10:00 AM start in Osaka lands at 10:30 AM in ACST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both Osaka and ACST are inside the 9-to-5 working day between 9:00 AM and 4:30 PM JST time (9:30 AM–5:00 PM ACST). That is roughly 7 hours 30 minutes of usable overlap.
- Watching a live event or market open: Osaka viewers need 9:30 AM in ACST to catch a 9:00 AM start there, and 11:30 PM if the event is anchored to Osaka.
- Always state the zone abbreviation, not just the hour. "3:00 PM JST" is unambiguous; "3 PM" across a +0h 30m gap is not.
- Block 9:00 AM–4:30 PM JST as the recurring meeting window if you work primarily from Osaka and need ACST colleagues present.
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.
About ACST (Australian Central Standard Time)
Australian Central Standard Time (ACST) is the half-hour offset of UTC+09:30 used across South Australia and the Northern Territory, taking in Adelaide and Darwin. South Australia moves to Australian Central Daylight Time (ACDT, UTC+10:30) from the first Sunday in October to the first Sunday in April, but the Northern Territory does not observe daylight saving — so Adelaide and Darwin sit 30 minutes apart in summer and level with each other in winter. The half-hour offset means Adelaide is 30 minutes behind Sydney in winter and level with it during daylight saving, which regularly catches out travellers and meeting planners.
Best time to call between Osaka and ACST
Both Osaka and ACST sit inside the 9 AM – 5 PM working day between 9:00 AM–4:30 PM JST, which is 9:30 AM–5:00 PM ACST. That gives roughly 7 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
Osaka and ACST share 7 hours of working-hours overlap (9:00 AM–4:30 PM JST), so scheduling a live meeting is straightforward.
Osaka is 30 minutes ahead of ACST (JST UTC+09:00 → ACST UTC+09:30). The shared working window is 9:00 AM–4:30 PM JST. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
Osaka
Does not observe DST
ACST
❄ Currently in Standard Time
Standard: UTC+09:30 · DST: UTC+10:30
Clocks spring forward on Sat, Oct 3, 2026
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 Osaka and ACST?
Osaka (JST, UTC+09:00) is 30 minutes ahead of ACST (ACST, UTC+09:30). The gap is currently +0h 30m.
How do I convert Osaka time to ACST time?
Add +0h 30m to Osaka local time. For example, 9:00 AM in Osaka is 9:30 AM in ACST.
What time is it in ACST right now?
ACST uses ACST at UTC+09:30. Use the live converter at the top of this page — it updates in real time and already accounts for the +0h 30m offset from Osaka.
What is the best time to call ACST from Osaka?
Call between 9:00 AM and 4:30 PM JST — that maps to 9:30 AM–5:00 PM ACST and keeps both parties inside the working day.
Which is ahead, Osaka or ACST?
Osaka is 30 minutes ahead of ACST. When it is 12:00 PM in Osaka it is 12:30 PM in ACST.
Do Osaka and ACST use different time zones?
Osaka (Japan) uses JST at UTC+09:00, while ACST uses ACST at UTC+09:30. The IANA identifiers are Asia/Tokyo and Australia/Adelaide.
Does daylight saving time affect the Osaka–ACST difference?
Neither zone observes daylight saving time, so the +0h 30m offset between Osaka and ACST is fixed all year.
Which other cities share Osaka's time zone?
JST also covers Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka and 1 more.
Which countries use JST, Osaka's zone?
JST is used in Japan.
Is there a day difference between Osaka and ACST?
Not normally. The +0h 30m gap only pushes the date over for late-evening times.
What is the time difference between Osaka and ACST?
ACST is +0h 30m from Osaka.
What timezone is Osaka in?
Osaka operates on Japan Standard Time (JST), UTC+9. As Japan's second economic center and a manufacturing hub, Osaka shares business hours with Tokyo.
What timezone is ACST in?
ACST operates on its local timezone.
What are the business hours in Osaka?
Standard business hours in Osaka are 9:00 AM - 6:00 PM JST.
Which countries use JST (Japan Standard Time)?
JST is used in Japan.
Does JST observe daylight saving time?
No, JST does not observe daylight saving time and remains at UTC+09:00 year-round.
What are some interesting facts about JST?
Japan does not observe daylight saving time. Tokyo is the most populous metropolitan area in the world.
Which cities are in the ACST timezone?
Major cities in the ACST timezone include Adelaide, Darwin, Alice Springs, Mount Gambier.
What is the UTC offset for ACST?
Australian Central Standard Time (ACST) is at UTC+09:30. During daylight saving time, it shifts to ACDT.
What should I know about the ACST timezone?
ACST uses a half-hour offset: UTC+09:30. South Australia moves to ACDT (UTC+10:30) in summer; the Northern Territory does not.
When is it midnight in Osaka, what time is it in ACST?
When it is 12:00 AM (midnight) in Osaka (JST), it is +0h 30m later in ACST (ACST).
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