Seoul to Honolulu
-19hSeoul
KSTSOURCEHonolulu
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).
About Seoul
WikipediaSeoul operates on Korea Standard Time (KST), UTC+9, same as Japan. As a global tech and entertainment hub, Seoul coordinates with East Asian markets.
Seoul has the fastest average internet speed in the world.
About Honolulu
WikipediaHonolulu operates on Hawaii Standard Time (HST), UTC-10 with no daylight saving. Hawaii's consistent time makes it a predictable connection between Asia and mainland USA.
Pearl Harbor memorial receives over 2 million visitors annually.
Seoul vs Honolulu: Offsets, DST and Best Call Times
Seoul runs on Korean Standard Time (KST) at UTC+09:00. Honolulu runs on Hawaii-Aleutian Standard Time (HST) at UTC-10:00. That puts Seoul 19 hours behind Honolulu — a difference of -19h at the current offsets.
In practice, when it is 9:00 AM in Seoul it is 2:00 PM in Honolulu on the previous day. Midnight in Seoul is 5:00 AM in Honolulu. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Seoul to Honolulu time conversion table
| Seoul (KST) | Honolulu (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 Seoul to Honolulu time
- Scheduling a call from Seoul to Honolulu: a 10:00 AM start in Seoul lands at 3:00 PM in Honolulu the previous day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -19h gap: Seoul and Honolulu 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 Honolulu is 2:00 PM in Seoul.
- Watching a live event or market open: Seoul viewers need 2:00 PM in Honolulu to catch a 9:00 AM start there, and 7:00 PM if the event is anchored to Seoul.
- 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 Seoul takes the early slot, the next week Honolulu 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 Seoul and Honolulu
With a -19h offset there is no overlap inside a normal 9 AM – 5 PM day. Honolulu opens at 9:00 AM HST, which is 2:00 PM in Seoul, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
Seoul and Honolulu have no shared working hours because of the -19h gap. Teams need to alternate early starts or rely on asynchronous handovers.
Seoul is 19 hours behind Honolulu (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 Seoul and Honolulu?
Seoul (KST, UTC+09:00) is 19 hours behind Honolulu (HST, UTC-10:00). The gap is currently -19h.
How do I convert Seoul time to Honolulu time?
Add -19h to Seoul local time. For example, 9:00 AM in Seoul is 2:00 PM in Honolulu (previous day).
What time is it in Honolulu right now?
Honolulu 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 Seoul.
What is the best time to call Honolulu from Seoul?
There is no shared working-hours window because of the -19h gap. The closest option is 1:00 PM in Seoul, which is 6:00 PM in Honolulu.
Which is behind, Seoul or Honolulu?
Seoul is 19 hours behind Honolulu. When it is 12:00 PM in Seoul it is 5:00 PM in Honolulu.
Do Seoul and Honolulu use different time zones?
Seoul (South Korea) uses KST at UTC+09:00, while Honolulu (USA) uses HST at UTC-10:00. The IANA identifiers are Asia/Seoul and Pacific/Honolulu.
Does daylight saving time affect the Seoul–Honolulu difference?
Neither zone observes daylight saving time, so the -19h offset between Seoul and Honolulu is fixed all year.
Which other cities share Seoul's time zone?
KST also covers Seoul, Busan, Incheon, Daegu, Daejeon, Pyongyang.
Which countries use KST, Seoul's zone?
KST is used in South Korea, North Korea.
Is there a day difference between Seoul and Honolulu?
Sometimes. The -19h gap is large enough that 8:00 PM or later in Seoul already falls on the in Honolulu.
What is the time difference between Seoul and Honolulu?
Honolulu is -19h from Seoul.
What timezone is Seoul in?
Seoul operates on Korea Standard Time (KST), UTC+9, same as Japan. As a global tech and entertainment hub, Seoul coordinates with East Asian markets.
What timezone is Honolulu in?
Honolulu operates on Hawaii Standard Time (HST), UTC-10 with no daylight saving. Hawaii's consistent time makes it a predictable connection between Asia and mainland USA.
What are the business hours in Seoul?
Standard business hours in Seoul are 9:00 AM - 6:00 PM KST.
What are the business hours in Honolulu?
Standard business hours in Honolulu are 8:00 AM - 5:00 PM HST.
What is the best time to schedule a call between Seoul and Honolulu?
The best overlap for a call is when both cities are in business hours. Seoul works 9:00 AM - 6:00 PM KST and Honolulu works 8:00 AM - 5:00 PM HST (-19h difference). Try scheduling during the overlapping window for maximum convenience.
What currencies are used in Seoul and Honolulu?
Seoul uses KRW (₩) while Honolulu uses USD ($). Check current exchange rates when planning travel or business between these cities.
How do Seoul and Honolulu compare in size?
Seoul has a population of approximately 9.7 million (metro: 25.5 million), while Honolulu has approximately 350,000 (metro: 1 million).
What are the major landmarks in Seoul and Honolulu?
Seoul is known for Gyeongbokgung Palace, N Seoul Tower, Bukchon Hanok Village. Honolulu is famous for Waikiki Beach, Diamond Head, Pearl Harbor.
Do Seoul and Honolulu have stock exchanges?
Yes. Seoul has the KRX (Korea Exchange) and Honolulu has the N/A (Uses NYSE/NASDAQ). The -19h time difference affects trading hour overlaps between these exchanges.
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 Seoul, what time is it in Honolulu?
When it is 12:00 AM (midnight) in Seoul (KST), it is -19h later in Honolulu (HST).
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