Offset
The time difference between Seoul and San José is 15 hours.
Seoul (KST) is ahead of San José (CST).
KST: UTC+9
CST: UTC-6
Neither Seoul nor San José is currently observing daylight saving time.
When to schedule
Standard business hours (9 AM–5 PM, Mon–Fri) in Seoul and San José don't overlap on the same weekday. San José is 15 hours behind Seoul.
Realistic options: hand off asynchronously, or stretch one side by an hour to catch the other team at the start or end of their day.
Public holidays in 2026
National public holidays can affect availability — a counterpart is likely off work on their own holidays, so it's worth planning meetings and deadlines around them.
South Korea
- New Year's DayThu, Jan 1
- Lunar New YearMon, Feb 16
- Lunar New YearTue, Feb 17
- Lunar New YearWed, Feb 18
- Independence Movement DayMon, Mar 2
- Labour DayFri, May 1
- Children's DayTue, May 5
- Buddha's BirthdayMon, May 25
- Local Election DayWed, Jun 3
- Memorial DaySat, Jun 6
- Constitution DayFri, Jul 17
- Liberation DayMon, Aug 17
- ChuseokThu, Sep 24
- ChuseokFri, Sep 25
- ChuseokSat, Sep 26
- National Foundation DayMon, Oct 5
- Hangul DayFri, Oct 9
- Christmas DayFri, Dec 25
Costa Rica
- New Year's DayThu, Jan 1
- Maundy ThursdayThu, Apr 2
- Good FridayFri, Apr 3
- Juan Santamaría DaySat, Apr 11
- Labour DayFri, May 1
- Annexation of the Party of Nicoya to Costa RicaSat, Jul 25
- Feast of Our Lady of the AngelsSun, Aug 2
- Mother's DaySat, Aug 15
- Independence DayTue, Sep 15
- Army Abolition DayTue, Dec 1
- Christmas DayFri, Dec 25
About these zones
Quick reference
Full 24-hour conversion table — tap any time to open it in the converter.
| Seoul | San José | Day |
|---|---|---|
| 12:00 am | 9:00 am | -1 day |
| 1:00 am | 10:00 am | -1 day |
| 2:00 am | 11:00 am | -1 day |
| 3:00 am | 12:00 pm | -1 day |
| 4:00 am | 1:00 pm | -1 day |
| 5:00 am | 2:00 pm | -1 day |
| 6:00 am | 3:00 pm | -1 day |
| 7:00 am | 4:00 pm | -1 day |
| 8:00 am | 5:00 pm | -1 day |
| 9:00 am | 6:00 pm | -1 day |
| 10:00 am | 7:00 pm | -1 day |
| 11:00 am | 8:00 pm | -1 day |
| 12:00 pm | 9:00 pm | -1 day |
| 1:00 pm | 10:00 pm | -1 day |
| 2:00 pm | 11:00 pm | -1 day |
| 3:00 pm | 12:00 am | Same day |
| 4:00 pm | 1:00 am | Same day |
| 5:00 pm | 2:00 am | Same day |
| 6:00 pm | 3:00 am | Same day |
| 7:00 pm | 4:00 am | Same day |
| 8:00 pm | 5:00 am | Same day |
| 9:00 pm | 6:00 am | Same day |
| 10:00 pm | 7:00 am | Same day |
| 11:00 pm | 8:00 am | Same day |
Daylight saving time
Neither Seoul nor San José observes daylight saving time. The offset between these zones remains constant year-round.
See the daylight saving time page for transition dates across every time zone.
Daylight today
- Sunrise
- 5:12 AM
- Sunset
- 7:52 PM
- Day length
- 14h 41m
- Sunrise
- 5:16 AM
- Sunset
- 5:57 PM
- Day length
- 12h 41m
Daylight overlap: 3h 45m — 5:12 AM–8:57 AM in Seoul (2:12 PM–5:57 PM in San José). Both locations are in daylight during this window.
Cities in these zones
Browse all cities to see the current local time anywhere.
Airports in these zones
Airports in Korea Standard Time
- GMP
- ICN
- PUS
- TAE
- CJJ
- KWJ
- MWX
Airports in Central Standard Time
- SJO
- SYQ
Related conversions
Common conversions
- What is 9:00 am Seoul in San José?
- 9:00 am Seoul is 6:00 pm San José, the previous day.
- What is 12:00 pm Seoul in San José?
- 12:00 pm Seoul is 9:00 pm San José, the previous day.
- What is 12:30 pm Seoul in San José?
- 12:30 pm Seoul is 9:30 pm San José, the previous day.
- What is 2:00 pm Seoul in San José?
- 2:00 pm Seoul is 11:00 pm San José, the previous day.
- What is 5:00 pm Seoul in San José?
- 5:00 pm Seoul is 2:00 am San José.
- What is 11:30 pm Seoul in San José?
- 11:30 pm Seoul is 8:30 am San José.