South Korea to HST
-19hSouth Korea
KSTSOURCEHST
HSTGreen rows indicate typical business hours (9 AM - 5 PM)
KST and HST on the World Map
The map below highlights the KST (Korea Standard Time) and HST (Hawaii 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).
HST – Hawaii Standard Time
UTC-10:00Hawaii Standard Time (HST) is the time zone for the Hawaiian Islands, 10 hours behind UTC.
- •Hawaii does not observe daylight saving time.
- •HST is 5 hours behind EST in winter and 6 hours behind EDT in summer.
- •Hawaii is one of only two US states that don't observe DST (the other is Arizona).
Comparing Time Zones: South Korea and HST
South Korea runs on Korean Standard Time (KST) at UTC+09:00. HST runs on Hawaii Standard Time (HST) at UTC-10:00. That puts South Korea 19 hours behind HST — a difference of -19h at the current offsets.
In practice, when it is 9:00 AM in South Korea it is 2:00 PM in HST on the previous day. Midnight in South Korea is 5:00 AM in HST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
South Korea to HST time conversion table
| South Korea (KST) | HST (HST) | Day |
|---|---|---|
| 12:00 AM | 5:00 AM | previous day |
| 6:00 AM | 11:00 AM | previous day |
| 7:00 AM | 12:00 PM | previous day |
| 8:00 AM | 1:00 PM | previous day |
| 9:00 AM | 2:00 PM | previous day |
| 12:00 PM | 5:00 PM | previous day |
| 3:00 PM | 8:00 PM | previous day |
| 5:00 PM | 10:00 PM | previous day |
| 6:00 PM | 11:00 PM | previous day |
| 9:00 PM | 2:00 AM | same day |
Why people convert South Korea to HST time
- Scheduling a call from South Korea to HST: a 10:00 AM start in South Korea lands at 3:00 PM in HST the previous day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -19h gap: South Korea and HST have no overlap inside a normal 9-to-5 day, so real-time meetings need an early-morning or late-evening slot on one side. 9:00 AM in HST is 2:00 PM in South Korea.
- Booking travel or deliveries: tracking HST local time against South Korea keeps pickup windows and arrival estimates honest across the -19h offset.
- Always state the zone abbreviation, not just the hour. "3:00 PM KST" is unambiguous; "3 PM" across a -19h gap is not.
- With a -19h gap there is no shared 9-to-5 window, so alternate the early start: one week South Korea takes the early slot, the next week HST does.
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 HST (Hawaii Standard Time)
Hawaii Standard Time (HST) is used in the state of Hawaii and does not observe daylight saving time. This makes HST one of the most consistent time zones in the US. The Hawaiian Islands are among the last places on Earth to see a new calendar day.
Best time to call between South Korea and HST
With a -19h offset there is no overlap inside a normal 9 AM – 5 PM day. HST opens at 9:00 AM HST, which is 2:00 PM in South Korea, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
South Korea and HST have no shared working hours because of the -19h gap. Teams need to alternate early starts or rely on asynchronous handovers.
South Korea is 19 hours behind HST (KST UTC+09:00 → HST UTC-10:00). There is no shared 9-to-5 window, so plan around an early or late slot. 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 South Korea and HST?
South Korea (KST, UTC+09:00) is 19 hours behind HST (HST, UTC-10:00). The gap is currently -19h.
How do I convert South Korea time to HST time?
Add -19h to South Korea local time. For example, 9:00 AM in South Korea is 2:00 PM in HST (previous day).
What time is it in HST right now?
HST uses HST at UTC-10:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -19h offset from South Korea.
What is the best time to call HST from South Korea?
There is no shared working-hours window because of the -19h gap. The closest option is 1:00 PM in South Korea, which is 6:00 PM in HST.
Which is behind, South Korea or HST?
South Korea is 19 hours behind HST. When it is 12:00 PM in South Korea it is 5:00 PM in HST.
Do South Korea and HST use different time zones?
South Korea (South Korea) uses KST at UTC+09:00, while HST uses HST at UTC-10:00. The IANA identifiers are Asia/Seoul and Pacific/Honolulu.
Does daylight saving time affect the South Korea–HST difference?
Neither zone observes daylight saving time, so the -19h offset between South Korea and HST is fixed all year.
Which other cities share South Korea's time zone?
KST also covers Seoul, Busan, Incheon, Daegu, Daejeon, Pyongyang.
Which countries use KST, South Korea's zone?
KST is used in South Korea, North Korea.
Is there a day difference between South Korea and HST?
Sometimes. The -19h gap is large enough that 8:00 PM or later in South Korea already falls on the in HST.
What is the time difference between South Korea and HST?
HST is -19h from South Korea.
What timezone is South Korea in?
South Korea operates on its local timezone.
What timezone is HST in?
HST operates on its local timezone.
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 HST timezone?
Major cities in the HST timezone include Honolulu, Hilo, Kailua, Pearl City, Kapolei.
What is the UTC offset for HST?
Hawaii Standard Time (HST) is at UTC-10:00.
What should I know about the HST timezone?
Hawaii does not observe daylight saving time. HST is 5 hours behind EST in winter and 6 hours behind EDT in summer.
When is it midnight in South Korea, what time is it in HST?
When it is 12:00 AM (midnight) in South Korea (KST), it is -19h later in HST (HST).
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