Japan to KST
+0hJapan
JSTSOURCEKST
KSTGreen rows indicate typical business hours (9 AM - 5 PM)
JST and KST on the World Map
The map below highlights the JST (Japan Standard Time) and KST (Korea 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.
KST – Korea Standard Time
UTC+09:00Korea Standard Time (KST) is the time zone for South Korea, 9 hours ahead of UTC.
- •South Korea does not observe daylight saving time.
- •Seoul is home to Samsung, LG, and Hyundai headquarters.
- •KST is the same offset as JST (UTC+09:00).
Japan vs KST: Offsets, DST and Best Call Times
Japan runs on Japan Standard Time (JST) at UTC+09:00. KST runs on Korea Standard Time (KST) at UTC+09:00. That puts Japan no time difference KST — a difference of +0h at the current offsets.
In practice, when it is 9:00 AM in Japan it is 9:00 AM in KST. Midnight in Japan is 12:00 AM in KST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Japan to KST time conversion table
| Japan (JST) | KST (KST) | Day |
|---|---|---|
| 12:00 AM | 12:00 AM | same day |
| 6:00 AM | 6:00 AM | same day |
| 7:00 AM | 7:00 AM | same day |
| 8:00 AM | 8:00 AM | same day |
| 9:00 AM | 9:00 AM | same day |
| 12:00 PM | 12:00 PM | same day |
| 3:00 PM | 3:00 PM | same day |
| 5:00 PM | 5:00 PM | same day |
| 6:00 PM | 6:00 PM | same day |
| 9:00 PM | 9:00 PM | same day |
Why people convert Japan to KST time
- Scheduling a call from Japan to KST: a 10:00 AM start in Japan lands at 10:00 AM in KST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both Japan and KST are inside the 9-to-5 working day between 9:00 AM and 5:00 PM JST time (9:00 AM–5:00 PM KST). That is roughly 8 hours of usable overlap.
- Booking travel or deliveries: tracking KST local time against Japan keeps pickup windows and arrival estimates honest across the +0h offset.
- Always state the zone abbreviation, not just the hour. "3:00 PM JST" is unambiguous; "3 PM" across a +0h gap is not.
- Block 9:00 AM–5:00 PM JST as the recurring meeting window if you work primarily from Japan and need KST 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 KST (Korea Standard Time)
Korea Standard Time (KST) is the time zone used in South Korea. It shares the same UTC offset as Japan Standard Time but is a distinct time zone. South Korea does not observe daylight saving time. Seoul, the capital, is a major global tech and business hub.
Best time to call between Japan and KST
Both Japan and KST sit inside the 9 AM – 5 PM working day between 9:00 AM–5:00 PM JST, which is 9:00 AM–5:00 PM KST. That gives roughly 8 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
Japan and KST share 8 hours of working-hours overlap (9:00 AM–5:00 PM JST), so scheduling a live meeting is straightforward.
Japan is no time difference KST (JST UTC+09:00 → KST UTC+09:00). The shared working window is 9:00 AM–5:00 PM JST. Remember to re-check around daylight-saving transitions.
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 Japan and KST?
Japan (JST, UTC+09:00) is no time difference KST (KST, UTC+09:00). The gap is currently +0h.
How do I convert Japan time to KST time?
Add +0h to Japan local time. For example, 9:00 AM in Japan is 9:00 AM in KST.
What time is it in KST right now?
KST uses KST at UTC+09:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +0h offset from Japan.
What is the best time to call KST from Japan?
Call between 9:00 AM and 5:00 PM JST — that maps to 9:00 AM–5:00 PM KST and keeps both parties inside the working day.
Which is ahead, Japan or KST?
Japan and KST are currently on the same clock.
Do Japan and KST use different time zones?
Japan (Japan) uses JST at UTC+09:00, while KST uses KST at UTC+09:00. The IANA identifiers are Asia/Tokyo and Asia/Seoul.
Does daylight saving time affect the Japan–KST difference?
Neither zone observes daylight saving time, so the +0h offset between Japan and KST is fixed all year.
Which other cities share Japan's time zone?
JST also covers Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka and 1 more.
Which countries use JST, Japan's zone?
JST is used in Japan.
What is the time difference between Japan and KST?
KST is +0h from Japan.
What timezone is Japan in?
Japan operates on its local timezone.
What timezone is KST in?
KST operates on its local timezone.
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 KST timezone?
Major cities in the KST timezone include Seoul, Busan, Incheon, Daegu, Daejeon, Pyongyang.
What is the UTC offset for KST?
Korea Standard Time (KST) is at UTC+09:00.
What should I know about the KST timezone?
South Korea does not observe daylight saving time. Seoul is home to Samsung, LG, and Hyundai headquarters.
When is it midnight in Japan, what time is it in KST?
When it is 12:00 AM (midnight) in Japan (JST), it is +0h later in KST (KST).
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