KST to Riyadh
-6hKST
KSTSOURCERiyadh
ASTGreen rows indicate typical business hours (9 AM - 5 PM)
KST and AST on the World Map
The map below highlights the KST (Korea Standard Time) and AST (Arabia 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).
AST – Arabia Standard Time
UTC+03:00Arabia Standard Time (AST, UTC+03:00) is the time zone for Saudi Arabia and the other Gulf states of the Arabian peninsula.
- •None of the Gulf states on Arabia Standard Time observe daylight saving.
- •AST is the same offset as Moscow Standard Time and East Africa Time.
- •Riyadh is one hour ahead of Central European Time in winter.
- •The AST abbreviation is shared with Atlantic Standard Time (UTC-04:00).
About Riyadh
WikipediaRiyadh operates on Arabia Standard Time (AST), UTC+3. As OPEC's de facto capital and home to Tadawul, Riyadh time impacts global energy markets.
Riyadh is growing rapidly as part of Saudi Vision 2030 modernization.
Comparing Time Zones: KST and Riyadh
KST runs on Korea Standard Time (KST) at UTC+09:00. Riyadh runs on Arabian Standard Time (AST) at UTC+03:00. That puts KST 6 hours behind Riyadh — a difference of -6h at the current offsets.
In practice, when it is 9:00 AM in KST it is 3:00 AM in Riyadh. Midnight in KST is 6:00 PM in Riyadh. Neither zone observes daylight saving time, so the offset between them stays constant all year.
KST to Riyadh time conversion table
| KST (KST) | Riyadh (AST) | Day |
|---|---|---|
| 12:00 AM | 6:00 PM | previous day |
| 6:00 AM | 12:00 AM | same day |
| 7:00 AM | 1:00 AM | same day |
| 8:00 AM | 2:00 AM | same day |
| 9:00 AM | 3:00 AM | same day |
| 12:00 PM | 6:00 AM | same day |
| 3:00 PM | 9:00 AM | same day |
| 5:00 PM | 11:00 AM | same day |
| 6:00 PM | 12:00 PM | same day |
| 9:00 PM | 3:00 PM | same day |
Why people convert KST to Riyadh time
- Scheduling a call from KST to Riyadh: a 10:00 AM start in KST lands at 4:00 AM in Riyadh, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both KST and Riyadh are inside the 9-to-5 working day between 3:00 PM and 5:00 PM KST time (9:00 AM–11:00 AM AST). That is roughly 2 hours of usable overlap.
- Coordinating a KST-based team with Riyadh 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 -6h gap is not.
- Block 3:00 PM–5:00 PM KST as the recurring meeting window if you work primarily from KST and need Riyadh 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 AST (Arabia Standard Time)
Arabia Standard Time (AST) is fixed at UTC+03:00 all year across Saudi Arabia, Qatar, Kuwait, Bahrain, Iraq and Yemen. None of these countries observes daylight saving time, so the offset never changes. The abbreviation collides with Atlantic Standard Time (UTC-04:00) used in eastern Canada and the Caribbean; this page covers the Arabian peninsula meaning. Arabia Standard Time is the same offset as Moscow Standard Time and East Africa Time, which makes scheduling with Europe straightforward — Riyadh is one hour ahead of Central European Time in winter and level with it during European summer time.
Best time to call between KST and Riyadh
Both KST and Riyadh sit inside the 9 AM – 5 PM working day between 3:00 PM–5:00 PM KST, which is 9:00 AM–11:00 AM AST. That gives roughly 2 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
KST and Riyadh overlap for about 2 hours during the working day — enough for meetings if you avoid the edges of the window.
KST is 6 hours behind Riyadh (KST UTC+09:00 → AST UTC+03:00). The shared working window is 3:00 PM–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 KST and Riyadh?
KST (KST, UTC+09:00) is 6 hours behind Riyadh (AST, UTC+03:00). The gap is currently -6h.
How do I convert KST time to Riyadh time?
Add -6h to KST local time. For example, 9:00 AM in KST is 3:00 AM in Riyadh.
What time is it in Riyadh right now?
Riyadh uses AST at UTC+03:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -6h offset from KST.
What is the best time to call Riyadh from KST?
Call between 3:00 PM and 5:00 PM KST — that maps to 9:00 AM–11:00 AM AST and keeps both parties inside the working day.
Which is behind, KST or Riyadh?
KST is 6 hours behind Riyadh. When it is 12:00 PM in KST it is 6:00 AM in Riyadh.
Do KST and Riyadh use different time zones?
KST uses KST at UTC+09:00, while Riyadh (Saudi Arabia) uses AST at UTC+03:00. The IANA identifiers are Asia/Seoul and Asia/Riyadh.
Does daylight saving time affect the KST–Riyadh difference?
Neither zone observes daylight saving time, so the -6h offset between KST and Riyadh is fixed all year.
Which other cities share KST's time zone?
KST also covers Seoul, Busan, Incheon, Daegu, Daejeon, Pyongyang.
Which countries use KST, KST's zone?
KST is used in South Korea, North Korea.
Is there a day difference between KST and Riyadh?
Not normally. The -6h gap only pushes the date over the previous day.
What is the time difference between KST and Riyadh?
Riyadh is -6h from KST.
What timezone is KST in?
KST operates on its local timezone.
What timezone is Riyadh in?
Riyadh operates on Arabia Standard Time (AST), UTC+3. As OPEC's de facto capital and home to Tadawul, Riyadh time impacts global energy markets.
What are the business hours in Riyadh?
Standard business hours in Riyadh are 8:00 AM - 4:00 PM AST (Sunday-Thursday).
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 AST timezone?
Major cities in the AST timezone include Riyadh, Jeddah, Doha, Kuwait City, Baghdad.
What is the UTC offset for AST?
Arabia Standard Time (AST) is at UTC+03:00.
What should I know about the AST timezone?
None of the Gulf states on Arabia Standard Time observe daylight saving. AST is the same offset as Moscow Standard Time and East Africa Time.
When is it midnight in KST, what time is it in Riyadh?
When it is 12:00 AM (midnight) in KST (KST), it is -6h later in Riyadh (AST).
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