Seoul to JST
+0hSeoul
KSTSOURCEJST
JSTGreen rows indicate typical business hours (9 AM - 5 PM)
KST and JST on the World Map
The map below highlights the KST (Korea Standard Time) and JST (Japan Standard Time) timezone regions across the globe.
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).
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.
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.
Comparing Time Zones: Seoul and JST
Seoul runs on Korean Standard Time (KST) at UTC+09:00. JST runs on Japan Standard Time (JST) at UTC+09:00. That puts Seoul no time difference JST — a difference of +0h at the current offsets.
In practice, when it is 9:00 AM in Seoul it is 9:00 AM in JST. Midnight in Seoul is 12:00 AM in JST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Seoul to JST time conversion table
| Seoul (KST) | JST (JST) | 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 Seoul to JST time
- Scheduling a call from Seoul to JST: a 10:00 AM start in Seoul lands at 10:00 AM in JST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both Seoul and JST are inside the 9-to-5 working day between 9:00 AM and 5:00 PM KST time (9:00 AM–5:00 PM JST). That is roughly 8 hours of usable overlap.
- Coordinating a Seoul-based team with JST contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
- Always state the zone abbreviation, not just the hour. "3:00 PM KST" is unambiguous; "3 PM" across a +0h gap is not.
- Block 9:00 AM–5:00 PM KST as the recurring meeting window if you work primarily from Seoul and need JST colleagues present.
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.
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 Seoul and JST
Both Seoul and JST sit inside the 9 AM – 5 PM working day between 9:00 AM–5:00 PM KST, which is 9:00 AM–5:00 PM JST. That gives roughly 8 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
Seoul and JST share 8 hours of working-hours overlap (9:00 AM–5:00 PM KST), so scheduling a live meeting is straightforward.
Seoul is no time difference JST (KST UTC+09:00 → JST UTC+09:00). The shared working window is 9:00 AM–5:00 PM KST. 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 Seoul and JST?
Seoul (KST, UTC+09:00) is no time difference JST (JST, UTC+09:00). The gap is currently +0h.
How do I convert Seoul time to JST time?
Add +0h to Seoul local time. For example, 9:00 AM in Seoul is 9:00 AM in JST.
What time is it in JST right now?
JST 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 +0h offset from Seoul.
What is the best time to call JST from Seoul?
Call between 9:00 AM and 5:00 PM KST — that maps to 9:00 AM–5:00 PM JST and keeps both parties inside the working day.
Which is ahead, Seoul or JST?
Seoul and JST are currently on the same clock.
Do Seoul and JST use different time zones?
Seoul (South Korea) uses KST at UTC+09:00, while JST uses JST at UTC+09:00. The IANA identifiers are Asia/Seoul and Asia/Tokyo.
Does daylight saving time affect the Seoul–JST difference?
Neither zone observes daylight saving time, so the +0h offset between Seoul and JST is fixed all year.
Which other cities share Seoul's time zone?
KST also covers Seoul, Busan, Incheon, Daegu, Daejeon, Pyongyang.
Which countries use KST, Seoul's zone?
KST is used in South Korea, North Korea.
What is the time difference between Seoul and JST?
JST is +0h from Seoul.
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 timezone is JST in?
JST operates on its local timezone.
What are the business hours in Seoul?
Standard business hours in Seoul are 9:00 AM - 6:00 PM KST.
Which countries use KST (Korea Standard Time)?
KST is used in South Korea, North Korea.
Does KST observe daylight saving time?
No, KST does not observe daylight saving time and remains at UTC+09:00 year-round.
What are some interesting facts about KST?
South Korea does not observe daylight saving time. Seoul is home to Samsung, LG, and Hyundai headquarters.
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 Seoul, what time is it in JST?
When it is 12:00 AM (midnight) in Seoul (KST), it is +0h later in JST (JST).
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