JST to KST Converter & Meeting Planner
Quick answer: 9:00 AM JST = 9:00 AM KST (fixed +09:00 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Japan Standard Time (JST) and Korea Standard Time (KST)? You need to account for the standard time difference. Korea Standard Time is normally 0 hours ahead of Japan Standard Time. Whether you are coordinating between teams in Tokyo and Osaka and Seoul and Busan, our live tool has you covered. Use our interactive overlap studio below to find the perfect waking hours for both regions, taking into account any seasonal Daylight Saving Time (DST) changes.
24-Hour Conversion Table
Quick reference: 12:00 AM JST = 12:00 AM KST. The full 24-hour JST to KST table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM JST = 3:00 PM KST.
| JST Time | KST Time |
|---|---|
| 12:00 AM (00:00) | 12:00 AM (00:00) |
| 1:00 AM (01:00) | 1:00 AM (01:00) |
| 2:00 AM (02:00) | 2:00 AM (02:00) |
| 3:00 AM (03:00) | 3:00 AM (03:00) |
| 4:00 AM (04:00) | 4:00 AM (04:00) |
| 5:00 AM (05:00) | 5:00 AM (05:00) |
| 6:00 AM (06:00) | 6:00 AM (06:00) |
| 7:00 AM (07:00) | 7:00 AM (07:00) |
| 8:00 AM (08:00) | 8:00 AM (08:00) |
| 9:00 AM (09:00) | 9:00 AM (09:00) |
| 10:00 AM (10:00) | 10:00 AM (10:00) |
| 11:00 AM (11:00) | 11:00 AM (11:00) |
| 12:00 PM (12:00) | 12:00 PM (12:00) |
| 1:00 PM (13:00) | 1:00 PM (13:00) |
| 2:00 PM (14:00) | 2:00 PM (14:00) |
| 3:00 PM (15:00) | 3:00 PM (15:00) |
| 4:00 PM (16:00) | 4:00 PM (16:00) |
| 5:00 PM (17:00) | 5:00 PM (17:00) |
| 6:00 PM (18:00) | 6:00 PM (18:00) |
| 7:00 PM (19:00) | 7:00 PM (19:00) |
| 8:00 PM (20:00) | 8:00 PM (20:00) |
| 9:00 PM (21:00) | 9:00 PM (21:00) |
| 10:00 PM (22:00) | 10:00 PM (22:00) |
| 11:00 PM (23:00) | 11:00 PM (23:00) |
Best time to call Seoul from Tokyo
For most work calls, compare the normal business day in Tokyo (JST) with the business day in Seoul (KST). JST commonly covers East Asia, while KST is mainly associated with East Asia.
⚠️ Note: 2026-07-04 is not a normal workday in one or both regions based on their configured calendar. The overlap below should be treated as a reference, not a guaranteed office-hours window.
✅ The most practical overlap on 2026-07-04 is usually 9:00 AM - 6:00 PM JST, which corresponds to 9:00 AM - 6:00 PM KST. This window sits inside the typical JST workday (9:00 AM - 6:00 PM) and the KST workday (9:00 AM - 6:00 PM).
- DST Safety: Neither JST nor KST uses Daylight Saving Time in our dataset, making business-hour relationships stable year-round.
- Tokyo Stock Exchange (TSE): 09:00-15:00 local time in Tokyo.
- Korea Exchange (KRX): 09:00-15:30 local time in Seoul.
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Frequently Asked Questions
What is the time difference between JST and KST?
During standard time, Korea Standard Time is 0 hours ahead of Japan Standard Time.
Does Japan observe Daylight Saving Time?
Japan has not observed Daylight Saving Time since 1951, when the practice introduced during the Allied occupation was abolished by the Japanese government. JST has remained fixed at UTC+9:00 ever since, and there is no current legislation to reintroduce DST in Japan.
Is JST the same as Korean Standard Time (KST)?
Yes, South Korea's Korean Standard Time (KST) operates at the same UTC+9:00 offset as JST, and South Korea also does not observe Daylight Saving Time. The two countries share an identical clock year-round, which simplifies scheduling for the significant trade, technology, and cultural exchange between Tokyo and Seoul.
Does South Korea observe Daylight Saving Time?
South Korea does not observe Daylight Saving Time and has not done so since 1988, when DST was discontinued following the Seoul Summer Olympics. KST remains fixed at UTC+9:00 every day of the year, meaning the offset between Seoul and any DST-observing country shifts by one hour twice annually when those countries change their clocks.
Are KST and JST the same?
Yes, Korea Standard Time (KST) and Japan Standard Time (JST) share the identical UTC+9:00 offset, and neither country observes Daylight Saving Time. Seoul and Tokyo run on exactly the same clock year-round, which directly supports the deep semiconductor, automotive, and consumer electronics supply chain integration between the two economies.