JST to Seoul
+0hJST
JSTSOURCESeoul
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).
About Seoul
WikipediaSeoul operates on Korea Standard Time (KST), UTC+9, same as Japan. As a global tech and entertainment hub, Seoul coordinates with East Asian markets.
Seoul has the fastest average internet speed in the world.
JST to Seoul Time Difference – Complete Guide
JST runs on Japan Standard Time (JST) at UTC+09:00. Seoul runs on Korean Standard Time (KST) at UTC+09:00. That puts JST no time difference Seoul — a difference of +0h at the current offsets.
In practice, when it is 9:00 AM in JST it is 9:00 AM in Seoul. Midnight in JST is 12:00 AM in Seoul. Neither zone observes daylight saving time, so the offset between them stays constant all year.
JST to Seoul time conversion table
| JST (JST) | Seoul (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 JST to Seoul time
- Scheduling a call from JST to Seoul: a 10:00 AM start in JST lands at 10:00 AM in Seoul, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both JST and Seoul 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.
- Watching a live event or market open: JST viewers need 9:00 AM in Seoul to catch a 9:00 AM start there, and 12:00 AM if the event is anchored to JST.
- 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 JST and need Seoul 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 JST and Seoul
Both JST and Seoul 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
JST and Seoul share 8 hours of working-hours overlap (9:00 AM–5:00 PM JST), so scheduling a live meeting is straightforward.
JST is no time difference Seoul (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 JST and Seoul?
JST (JST, UTC+09:00) is no time difference Seoul (KST, UTC+09:00). The gap is currently +0h.
How do I convert JST time to Seoul time?
Add +0h to JST local time. For example, 9:00 AM in JST is 9:00 AM in Seoul.
What time is it in Seoul right now?
Seoul 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 JST.
What is the best time to call Seoul from JST?
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, JST or Seoul?
JST and Seoul are currently on the same clock.
Do JST and Seoul use different time zones?
JST uses JST at UTC+09:00, while Seoul (South Korea) uses KST at UTC+09:00. The IANA identifiers are Asia/Tokyo and Asia/Seoul.
Does daylight saving time affect the JST–Seoul difference?
Neither zone observes daylight saving time, so the +0h offset between JST and Seoul is fixed all year.
Which other cities share JST's time zone?
JST also covers Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka and 1 more.
Which countries use JST, JST's zone?
JST is used in Japan.
What is the time difference between JST and Seoul?
Seoul is +0h from JST.
What timezone is JST in?
JST operates on its local timezone.
What timezone is Seoul in?
Seoul operates on Korea Standard Time (KST), UTC+9, same as Japan. As a global tech and entertainment hub, Seoul coordinates with East Asian markets.
What are the business hours in Seoul?
Standard business hours in Seoul are 9:00 AM - 6:00 PM KST.
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 JST, what time is it in Seoul?
When it is 12:00 AM (midnight) in JST (JST), it is +0h later in Seoul (KST).
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