Convert KST to JST
See the live time match between Korea Standard Time and Japan Standard Time, compare hours, and plan calls without offset confusion.
How to Convert KST to JST
Open the KST to JST converter: Go to https://www.xconvert.com/time-converter/kst-to-jst-converter. The page loads with KST and JST as the primary comparison, which is useful if you are scheduling a supplier call between Seoul and Tokyo, coordinating a gaming launch across South Korea and Japan, or checking handoff times for regional support teams.
Add relevant comparison cities: Click “+ Add City” to add cities such as Seoul, Tokyo, and optionally Singapore or Los Angeles if your team also includes APAC headquarters or a US stakeholder. This is especially practical for electronics, automotive, shipping, and media teams, since companies operating across Korea and Japan often also coordinate with regional hubs in Singapore and overnight teams in North America.
Drag to select a meeting window: Use the “Select” button to switch into selection mode, then drag across the timeline on the KST row to highlight a time range in purple. For example, drag from 9:00 AM to 11:00 AM KST and you will see the exact same 9:00 AM to 11:00 AM JST, confirming that a Seoul morning meeting appears at the same local clock time in Tokyo because both zones are UTC+9 with no seasonal offset change.
Export and share the selected time: After selecting the range, use the export options for ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. This is useful when sending a confirmed meeting slot to a Korean manufacturing partner and a Japanese client, because everyone receives the event in their own calendar without needing to recalculate the time manually.
Understanding the KST to JST Time Difference
KST (Korea Standard Time) and JST (Japan Standard Time) have an exact time difference of 0 hours. Both time zones run on UTC+9, so 9:00 AM KST is 9:00 AM JST, 3:00 PM KST is 3:00 PM JST, and midnight in Seoul is also midnight in Tokyo.
Daylight saving time does not currently affect either time zone. South Korea does not observe DST, and Japan does not observe DST either, so the difference between KST and JST stays the same in January, April, July, October, and every other month of the year. There are no spring-forward or fall-back dates to track, which makes recurring meetings between Korean and Japanese teams much easier than meetings involving the US or Europe.
This fixed alignment is valuable for industries with frequent cross-border coordination. South Korea and Japan are both major centers for electronics, semiconductors, automotive manufacturing, shipping, gaming, finance, and media distribution, and the zero-hour difference means operating hours line up naturally. For example, a logistics team in Busan and a port operations contact in Yokohama can work from the same clock schedule without worrying about seasonal shifts.
In real-world geographic terms, KST is used across South Korea, including Seoul, Busan, Incheon, and Daegu, while JST is used across Japan, including Tokyo, Osaka, Nagoya, Fukuoka, and Sapporo. Seoul has a population of about 9.4 million in the city proper, while Tokyo’s 23 special wards have roughly 9.7 million residents, and the wider Tokyo metropolitan area is the largest urban economy in the world. Because both countries operate on the same UTC offset, travel planning, flight coordination, and same-day business scheduling are straightforward.
Best Times for Calls and Meetings Between KST and JST
Because KST and JST are the same time zone in practice, the best meeting windows are simply the hours that work well on both sides of the business day. A standard office overlap of 9:00 AM to 6:00 PM KST = 9:00 AM to 6:00 PM JST gives a full 9-hour shared workday, which is unusually convenient for international coordination.
For formal business calls, the most practical slots are usually:
- 9:00 AM to 11:00 AM KST = 9:00 AM to 11:00 AM JST
- 1:00 PM to 3:00 PM KST = 1:00 PM to 3:00 PM JST
- 3:00 PM to 5:00 PM KST = 3:00 PM to 5:00 PM JST
These windows work well for companies handling procurement, engineering reviews, or account management between Seoul and Tokyo. A 10:00 AM KST meeting lands at 10:00 AM JST, which is early enough for teams to act on decisions the same day, while a 4:00 PM KST call is still 4:00 PM JST, making it suitable for end-of-day status checks without pushing either side into evening hours.
If your teams follow stricter work-hour policies, a narrower overlap of 10:00 AM to 4:00 PM is often ideal for decision-making meetings. This avoids the first hour of the day, when teams are often handling email and standups, and avoids late-afternoon scheduling that can conflict with factory reporting, trading close tasks, or commuter travel in large metro areas such as Seoul and Tokyo.
For travel and transport coordination, the identical time zone also reduces confusion around departures and arrivals. A flight itinerary, hotel check-in time, or conference session listed in Tokyo time can be read the same way by someone in Seoul. This is particularly helpful on busy routes such as Seoul Incheon (ICN) to Tokyo Haneda (HND) or Narita (NRT), where same-day business travel is common.
Frequently Asked Questions
What is the time difference between KST and JST?
The time difference between KST and JST is 0 hours. Both are set to UTC+9, so the local clock time is the same in South Korea and Japan throughout the entire year.
This means there is no need to add or subtract hours when converting between the two. If it is 2:30 PM in Seoul, it is also 2:30 PM in Tokyo, which makes scheduling much simpler than with regions that change clocks seasonally.
When is 9 AM KST in JST?
9:00 AM KST is 9:00 AM JST. Since both time zones use the same UTC offset, the conversion is one-to-one with no adjustment required.
This is especially useful for recurring meetings, such as weekday standups, client check-ins, or regional operations calls. If a Korean team books a meeting for 9 AM KST every Tuesday, the Japanese team joins at 9 AM JST every Tuesday as well.
Does the difference between KST and JST change during DST?
No, the difference does not change during daylight saving time because neither South Korea nor Japan currently observes DST. The offset remains UTC+9 in both places in every month of the year.
That means there are no dates in March, October, or November when the relationship shifts, unlike time comparisons involving New York, London, or Sydney. For long-term planning, this stability is a major advantage because calendar invites remain consistent all year.
What is the best meeting time between KST and JST?
The best meeting time between KST and JST is usually any standard business-hour slot, since both sides share the same clock. Common choices include 10:00 AM to 11:00 AM for planning calls, 1:00 PM to 2:00 PM for post-lunch reviews, and 3:00 PM to 4:00 PM for project updates.
In practical terms, the best slot depends more on team routines than time conversion. Manufacturing teams may prefer late morning after shift check-ins, while media, gaming, and software teams often use early afternoon for cross-border collaboration.
Is Seoul the same time as Tokyo?
Yes, Seoul and Tokyo are on the same current time because Seoul uses KST (UTC+9) and Tokyo uses JST (UTC+9). There is no hour difference between the two capitals.
This is helpful for business travelers and remote teams because a calendar event, train connection, or conference session keeps the same local clock reading in both cities. If your Tokyo client suggests 4 PM, your Seoul office can also read that as 4 PM without conversion.
Why is KST to JST conversion so easy compared with other time zones?
KST to JST conversion is easy because both time zones have the same UTC offset and neither changes for daylight saving time. There are no seasonal adjustments, no previous-day or next-day shifts, and no partial-hour differences.
That simplicity matters for industries that rely on precise timing, such as shipping, semiconductors, automotive supply chains, and financial reporting. Teams can set recurring meetings, shipment cutoffs, and service windows without revisiting the schedule every spring or autumn.
Can I use the converter for travel planning between Korea and Japan?
Yes, the converter is useful for travel planning because departure, arrival, and meeting times stay aligned between KST and JST. If your hotel check-in is 3:00 PM in Tokyo, that is also 3:00 PM by Seoul time, so there is no mental adjustment needed after landing.
This is particularly helpful on high-frequency business routes between Seoul, Busan, Tokyo, Osaka, and Fukuoka. It reduces confusion when coordinating airport pickup, conference registration, restaurant reservations, or same-day return flights.