HST to JST Converter
Understanding HST and JST Time Zones
Hawaii Standard Time (HST)
Hawaii Standard Time is observed in undefined and uses the offset UTC-10. Major cities in this time zone include Honolulu, Maui. This time zone serves a significant global region with important economic and cultural hubs.
Japan Standard Time (JST)
Japan Standard Time operates at UTC+9, covering undefined. Key cities include Tokyo, Osaka, Yokohama. The 19-hour forward offset from HST means that when professionals in Honolulu start their workday at 9:00 AM, it is already 4:00 AM in Tokyo.
HST is also commonly referred to as Hawaii Time, Honolulu time, Hawaiian time. JST is also known as Japan time, Tokyo time, Japanese time. So if you are searching for Hawaii Time to Japan time, this is the same conversion as HST to JST.
Complete HST to JST Conversion Table
The table below shows every two-hour increment converted from Hawaii Standard Time to Japan Standard Time. Business hours (9 AM – 5 PM) are highlighted for easy scheduling reference.
| HST (Hawaii Standard Time) | JST (Japan Standard Time) |
|---|---|
| 12:00 AM (00:00) | 7:00 PM (19:00) |
| 2:00 AM (02:00) | 9:00 PM (21:00) |
| 4:00 AM (04:00) | 11:00 PM (23:00) |
| 6:00 AM (06:00) | 1:00 AM (01:00) (next day) |
| 8:00 AM (08:00) | 3:00 AM (03:00) (next day) |
| 10:00 AM (10:00) | 5:00 AM (05:00) (next day) |
| 12:00 PM (12:00) | 7:00 AM (07:00) (next day) |
| 2:00 PM (14:00) | 9:00 AM (09:00) (next day) |
| 4:00 PM (16:00) | 11:00 AM (11:00) (next day) |
| 6:00 PM (18:00) | 1:00 PM (13:00) (next day) |
| 8:00 PM (20:00) | 3:00 PM (15:00) (next day) |
| 10:00 PM (22:00) | 5:00 PM (17:00) (next day) |
Times shown in 12-hour and 24-hour format. Last updated 2026-03-09.
Scheduling Between HST and JST
When coordinating deliverables across HST and JST, set deadlines in the earlier time zone to avoid end-of-day confusion. A "5 PM deadline" should specify which zone to prevent missed deliveries due to the 19-hour offset.
The large 19-hour gap between HST and JST means that finding overlapping working hours requires compromise from at least one side. Consider adopting asynchronous workflows — recorded video updates, shared documents, and time-zone-aware project management tools — to supplement the limited real-time overlap.
Travel Between Honolulu and Tokyo
Flight times between Honolulu and Tokyo often appear misleading because of the time zone shift. A departure at 10:00 AM HST arriving at 7:00 PM JST may look long, but remember to factor in the 19-hour offset.
Medical experts recommend allowing approximately one day of adjustment per hour of time difference. For the 19-hour shift between HST and JST, plan for roughly one week of gradual adjustment for optimal performance.
Daylight Saving Time Considerations
Countries near the equator — including Singapore, most of Africa, and parts of South America — do not observe DST, making their offsets constant year-round. This simplifies scheduling compared to US or European zones.
For the HST to JST conversion specifically: HST (UTC-10) and JST (UTC+9) neither observes DST, so the 19-hour offset remains constant throughout the year. This makes scheduling reliable and predictable.
Related Time Zone Conversions
References & Resources
Frequently Asked Questions
HST (Hawaii Standard Time) is 19 hours behind JST (Japan Standard Time). HST is UTC-10 and JST is UTC+9.
When it is 12:00 PM (noon) in HST, it is 7:00 AM (next day) in JST.
The best overlap for business hours is approximately 4:00 AM to 12:00 PM JST, which corresponds to 9:00 AM to 5:00 PM in HST. Given the large gap, consider alternating between early and late meeting times.
Countries near the equator — including Singapore, most of Africa, and parts of South America — do not observe DST, making their offsets constant year-round. This simplifies scheduling compared to US or European zones.