IRST to South Korea
+5h 30mIRST
IRSTSOURCESouth Korea
KSTGreen rows indicate typical business hours (9 AM - 5 PM)
IRST and KST on the World Map
The map below highlights the IRST (Iran Standard Time) and KST (Korea Standard Time) timezone regions across the globe.
IRST – Iran Standard Time
UTC+03:30Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.
- •IRST is one of only a few time zones with a 30-minute offset.
- •Iran observes daylight saving time, switching to IRDT (UTC+04:30).
- •Tehran has a metropolitan population of over 16 million.
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).
Time Conversion Guide: IRST to South Korea
IRST runs on Iran Standard Time (IRST) at UTC+03:30. South Korea runs on Korean Standard Time (KST) at UTC+09:00. That puts IRST 5 hours 30 minutes ahead of South Korea — a difference of +5h 30m at the current offsets.
In practice, when it is 9:00 AM in IRST it is 2:30 PM in South Korea. Midnight in IRST is 5:30 AM in South Korea. Neither zone observes daylight saving time, so the offset between them stays constant all year.
IRST to South Korea time conversion table
| IRST (IRST) | South Korea (KST) | Day |
|---|---|---|
| 12:00 AM | 5:30 AM | same day |
| 6:00 AM | 11:30 AM | same day |
| 7:00 AM | 12:30 PM | same day |
| 8:00 AM | 1:30 PM | same day |
| 9:00 AM | 2:30 PM | same day |
| 12:00 PM | 5:30 PM | same day |
| 3:00 PM | 8:30 PM | same day |
| 5:00 PM | 10:30 PM | same day |
| 6:00 PM | 11:30 PM | same day |
| 9:00 PM | 2:30 AM | next day |
Why people convert IRST to South Korea time
- Scheduling a call from IRST to South Korea: a 10:00 AM start in IRST lands at 3:30 PM in South Korea, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both IRST and South Korea are inside the 9-to-5 working day between 9:00 AM and 11:30 AM IRST time (2:30 PM–5:00 PM KST). That is roughly 2 hours 30 minutes of usable overlap.
- Booking travel or deliveries: tracking South Korea local time against IRST keeps pickup windows and arrival estimates honest across the +5h 30m offset.
- Always state the zone abbreviation, not just the hour. "3:00 PM IRST" is unambiguous; "3 PM" across a +5h 30m gap is not.
- Block 9:00 AM–11:30 AM IRST as the recurring meeting window if you work primarily from IRST and need South Korea colleagues present.
About IRST (Iran Standard Time)
Iran Standard Time (IRST) is one of the few time zones with a 30-minute offset. Iran observes daylight saving time (IRDT, UTC+04:30) from late March to late September. Tehran, the capital, is one of the largest cities in the Middle East.
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 IRST and South Korea
Both IRST and South Korea sit inside the 9 AM – 5 PM working day between 9:00 AM–11:30 AM IRST, which is 2:30 PM–5:00 PM KST. That gives roughly 2 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
IRST and South Korea overlap for about 2 hours during the working day — enough for meetings if you avoid the edges of the window.
IRST is 5 hours 30 minutes ahead of South Korea (IRST UTC+03:30 → KST UTC+09:00). The shared working window is 9:00 AM–11:30 AM IRST. 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 IRST and South Korea?
IRST (IRST, UTC+03:30) is 5 hours 30 minutes ahead of South Korea (KST, UTC+09:00). The gap is currently +5h 30m.
How do I convert IRST time to South Korea time?
Add +5h 30m to IRST local time. For example, 9:00 AM in IRST is 2:30 PM in South Korea.
What time is it in South Korea right now?
South Korea 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 +5h 30m offset from IRST.
What is the best time to call South Korea from IRST?
Call between 9:00 AM and 11:30 AM IRST — that maps to 2:30 PM–5:00 PM KST and keeps both parties inside the working day.
Which is ahead, IRST or South Korea?
IRST is 5 hours 30 minutes ahead of South Korea. When it is 12:00 PM in IRST it is 5:30 PM in South Korea.
Do IRST and South Korea use different time zones?
IRST uses IRST at UTC+03:30, while South Korea (South Korea) uses KST at UTC+09:00. The IANA identifiers are Asia/Tehran and Asia/Seoul.
Does daylight saving time affect the IRST–South Korea difference?
Neither zone observes daylight saving time, so the +5h 30m offset between IRST and South Korea is fixed all year.
Which other cities share IRST's time zone?
IRST also covers Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
Which countries use IRST, IRST's zone?
IRST is used in Iran.
Is there a day difference between IRST and South Korea?
Not normally. The +5h 30m gap only pushes the date over for late-evening times.
What is the time difference between IRST and South Korea?
South Korea is +5h 30m from IRST.
What timezone is IRST in?
IRST operates on its local timezone.
What timezone is South Korea in?
South Korea operates on its local timezone.
Which countries use IRST (Iran Standard Time)?
IRST is used in Iran.
Does IRST observe daylight saving time?
Yes, IRST switches to IRDT during summer months.
What are some interesting facts about IRST?
IRST is one of only a few time zones with a 30-minute offset. Iran observes daylight saving time, switching to IRDT (UTC+04:30).
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 IRST, what time is it in South Korea?
When it is 12:00 AM (midnight) in IRST (IRST), it is +5h 30m later in South Korea (KST).
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