JST to Colombo
-3h 30mJST
JSTSOURCEColombo
ISTGreen rows indicate typical business hours (9 AM - 5 PM)
JST and IST on the World Map
The map below highlights the JST (Japan Standard Time) and IST (India Standard Time) timezone regions across the globe.
JST – Japan Standard Time
UTC+09:00Japan Standard Time (JST) is the time zone for Japan, 9 hours ahead of UTC.
- •Japan does not observe daylight saving time.
- •Tokyo is the most populous metropolitan area in the world.
- •The Tokyo Stock Exchange operates from 9:00 AM to 3:00 PM JST.
- •JST is 14 hours ahead of EST and 9 hours ahead of GMT.
IST – India Standard Time
UTC+05:30India Standard Time (IST) is the time zone for India and Sri Lanka, 5 hours and 30 minutes ahead of UTC.
- •India is 10 hours 30 minutes ahead of EST and 5 hours 30 minutes ahead of GMT.
- •India uses a single time zone despite spanning 30° of longitude.
- •IST is one of only a handful of time zones with a 30-minute offset.
- •IST is the most populous single time zone in the world with over 1.4 billion people.
- •The Bombay Stock Exchange (BSE) and National Stock Exchange (NSE) operate on IST.
About Colombo
WikipediaColombo operates on Sri Lanka Time (SLST), UTC+5:30. Sharing India's timezone, Colombo is a key South Asian trade and tourism hub.
Sri Lanka Standard Time (SLST) uses UTC+5:30, same offset as India.
Understanding the -3h 30m Gap: JST vs Colombo
JST runs on Japan Standard Time (JST) at UTC+09:00. Colombo runs on India Standard Time (IST) at UTC+05:30. That puts JST 3 hours 30 minutes behind Colombo — a difference of -3h 30m at the current offsets.
In practice, when it is 9:00 AM in JST it is 5:30 AM in Colombo. Midnight in JST is 8:30 PM in Colombo. Neither zone observes daylight saving time, so the offset between them stays constant all year.
JST to Colombo time conversion table
| JST (JST) | Colombo (IST) | Day |
|---|---|---|
| 12:00 AM | 8:30 PM | previous day |
| 6:00 AM | 2:30 AM | same day |
| 7:00 AM | 3:30 AM | same day |
| 8:00 AM | 4:30 AM | same day |
| 9:00 AM | 5:30 AM | same day |
| 12:00 PM | 8:30 AM | same day |
| 3:00 PM | 11:30 AM | same day |
| 5:00 PM | 1:30 PM | same day |
| 6:00 PM | 2:30 PM | same day |
| 9:00 PM | 5:30 PM | same day |
Why people convert JST to Colombo time
- Scheduling a call from JST to Colombo: a 10:00 AM start in JST lands at 6:30 AM in Colombo, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both JST and Colombo are inside the 9-to-5 working day between 12:30 PM and 5:00 PM JST time (9:00 AM–1:30 PM IST). That is roughly 4 hours 30 minutes of usable overlap.
- Booking travel or deliveries: tracking Colombo local time against JST keeps pickup windows and arrival estimates honest across the -3h 30m offset.
- Always state the zone abbreviation, not just the hour. "3:00 PM JST" is unambiguous; "3 PM" across a -3h 30m gap is not.
- Block 12:30 PM–5:00 PM JST as the recurring meeting window if you work primarily from JST and need Colombo colleagues present.
About JST (Japan Standard Time)
Japan Standard Time (JST) is the standard time zone for all of Japan. Japan does not observe daylight saving time. JST is 9 hours ahead of UTC and 14 hours ahead of EST. The Tokyo Stock Exchange, the world's third largest by market capitalization, operates on JST. South Korea uses the same offset (KST) but it is a distinct time zone.
About IST (India Standard Time)
India Standard Time (IST) is the time observed throughout India and Sri Lanka. It is based on the 82.5°E meridian, passing through Mirzapur in Uttar Pradesh. India uses a single time zone despite spanning roughly 30° of longitude, which has been debated. IST does not observe daylight saving time. India is the world's most populous country, making IST one of the most-used time zones globally. The IT outsourcing industry and call centers operate primarily on IST, making the EST-to-IST conversion one of the most searched timezone conversions.
Best time to call between JST and Colombo
Both JST and Colombo sit inside the 9 AM – 5 PM working day between 12:30 PM–5:00 PM JST, which is 9:00 AM–1:30 PM IST. That gives roughly 4 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
JST and Colombo overlap for about 4 hours during the working day — enough for meetings if you avoid the edges of the window.
JST is 3 hours 30 minutes behind Colombo (JST UTC+09:00 → IST UTC+05:30). The shared working window is 12:30 PM–5:00 PM JST. 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 JST and Colombo?
JST (JST, UTC+09:00) is 3 hours 30 minutes behind Colombo (IST, UTC+05:30). The gap is currently -3h 30m.
How do I convert JST time to Colombo time?
Add -3h 30m to JST local time. For example, 9:00 AM in JST is 5:30 AM in Colombo.
What time is it in Colombo right now?
Colombo uses IST at UTC+05:30. Use the live converter at the top of this page — it updates in real time and already accounts for the -3h 30m offset from JST.
What is the best time to call Colombo from JST?
Call between 12:30 PM and 5:00 PM JST — that maps to 9:00 AM–1:30 PM IST and keeps both parties inside the working day.
Which is behind, JST or Colombo?
JST is 3 hours 30 minutes behind Colombo. When it is 12:00 PM in JST it is 8:30 AM in Colombo.
Do JST and Colombo use different time zones?
JST uses JST at UTC+09:00, while Colombo (Sri Lanka) uses IST at UTC+05:30. The IANA identifiers are Asia/Tokyo and Asia/Colombo.
Does daylight saving time affect the JST–Colombo difference?
Neither zone observes daylight saving time, so the -3h 30m offset between JST and Colombo is fixed all year.
Which other cities share JST's time zone?
JST also covers Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka and 1 more.
Which countries use JST, JST's zone?
JST is used in Japan.
Is there a day difference between JST and Colombo?
Not normally. The -3h 30m gap only pushes the date over the previous day.
What is the time difference between JST and Colombo?
Colombo is -3h 30m from JST.
What timezone is JST in?
JST operates on its local timezone.
What timezone is Colombo in?
Colombo operates on Sri Lanka Time (SLST), UTC+5:30. Sharing India's timezone, Colombo is a key South Asian trade and tourism hub.
What are the business hours in Colombo?
Standard business hours in Colombo are 9:00 AM - 5:00 PM IST.
Which countries use JST (Japan Standard Time)?
JST is used in Japan.
Does JST observe daylight saving time?
No, JST does not observe daylight saving time and remains at UTC+09:00 year-round.
What are some interesting facts about JST?
Japan does not observe daylight saving time. Tokyo is the most populous metropolitan area in the world.
Which cities are in the IST timezone?
Major cities in the IST timezone include Mumbai, Delhi, Bangalore, Kolkata, Chennai, Hyderabad, Pune, Ahmedabad.
What is the UTC offset for IST?
India Standard Time (IST) is at UTC+05:30.
What should I know about the IST timezone?
India is 10 hours 30 minutes ahead of EST and 5 hours 30 minutes ahead of GMT. India uses a single time zone despite spanning 30° of longitude.
When is it midnight in JST, what time is it in Colombo?
When it is 12:00 AM (midnight) in JST (JST), it is -3h 30m later in Colombo (IST).
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