Osaka to Tehran
-5h 30mOsaka
JSTSOURCETehran
IRSTGreen rows indicate typical business hours (9 AM - 5 PM)
JST and IRST on the World Map
The map below highlights the JST (Japan Standard Time) and IRST (Iran 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.
IRST – Iran Standard Time
UTC+03:30Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.
- •IRST is one of only a few time zones with a 30-minute offset.
- •Iran observes daylight saving time, switching to IRDT (UTC+04:30).
- •Tehran has a metropolitan population of over 16 million.
About Osaka
WikipediaOsaka operates on Japan Standard Time (JST), UTC+9. As Japan's second economic center and a manufacturing hub, Osaka shares business hours with Tokyo.
Osaka Castle was originally built in 1583 and has been rebuilt several times.
About Tehran
WikipediaTehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
Iran Standard Time (IRST) is one of few timezones with a 30-minute offset (UTC+3:30).
Osaka to Tehran Time Difference – Complete Guide
Osaka runs on Japan Standard Time (JST) at UTC+09:00. Tehran runs on Iran Standard Time (IRST) at UTC+03:30. That puts Osaka 5 hours 30 minutes behind Tehran — a difference of -5h 30m at the current offsets.
In practice, when it is 9:00 AM in Osaka it is 3:30 AM in Tehran. Midnight in Osaka is 6:30 PM in Tehran. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Osaka to Tehran time conversion table
| Osaka (JST) | Tehran (IRST) | Day |
|---|---|---|
| 12:00 AM | 6:30 PM | previous day |
| 6:00 AM | 12:30 AM | same day |
| 7:00 AM | 1:30 AM | same day |
| 8:00 AM | 2:30 AM | same day |
| 9:00 AM | 3:30 AM | same day |
| 12:00 PM | 6:30 AM | same day |
| 3:00 PM | 9:30 AM | same day |
| 5:00 PM | 11:30 AM | same day |
| 6:00 PM | 12:30 PM | same day |
| 9:00 PM | 3:30 PM | same day |
Why people convert Osaka to Tehran time
- Scheduling a call from Osaka to Tehran: a 10:00 AM start in Osaka lands at 4:30 AM in Tehran, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both Osaka and Tehran are inside the 9-to-5 working day between 2:30 PM and 5:00 PM JST time (9:00 AM–11:30 AM IRST). That is roughly 2 hours 30 minutes of usable overlap.
- Keeping family and friends in sync: knowing that 8:00 PM in Osaka is 2:30 PM in Tehran makes it easy to avoid calling at 3 AM.
- Always state the zone abbreviation, not just the hour. "3:00 PM JST" is unambiguous; "3 PM" across a -5h 30m gap is not.
- Block 2:30 PM–5:00 PM JST as the recurring meeting window if you work primarily from Osaka and need Tehran 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 IRST (Iran Standard Time)
Iran Standard Time (IRST) is one of the few time zones with a 30-minute offset. Iran observes daylight saving time (IRDT, UTC+04:30) from late March to late September. Tehran, the capital, is one of the largest cities in the Middle East.
Best time to call between Osaka and Tehran
Both Osaka and Tehran sit inside the 9 AM – 5 PM working day between 2:30 PM–5:00 PM JST, which is 9:00 AM–11:30 AM IRST. That gives roughly 2 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
Osaka and Tehran overlap for about 2 hours during the working day — enough for meetings if you avoid the edges of the window.
Osaka is 5 hours 30 minutes behind Tehran (JST UTC+09:00 → IRST UTC+03:30). The shared working window is 2:30 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 Osaka and Tehran?
Osaka (JST, UTC+09:00) is 5 hours 30 minutes behind Tehran (IRST, UTC+03:30). The gap is currently -5h 30m.
How do I convert Osaka time to Tehran time?
Add -5h 30m to Osaka local time. For example, 9:00 AM in Osaka is 3:30 AM in Tehran.
What time is it in Tehran right now?
Tehran uses IRST at UTC+03:30. Use the live converter at the top of this page — it updates in real time and already accounts for the -5h 30m offset from Osaka.
What is the best time to call Tehran from Osaka?
Call between 2:30 PM and 5:00 PM JST — that maps to 9:00 AM–11:30 AM IRST and keeps both parties inside the working day.
Which is behind, Osaka or Tehran?
Osaka is 5 hours 30 minutes behind Tehran. When it is 12:00 PM in Osaka it is 6:30 AM in Tehran.
Do Osaka and Tehran use different time zones?
Osaka (Japan) uses JST at UTC+09:00, while Tehran (Iran) uses IRST at UTC+03:30. The IANA identifiers are Asia/Tokyo and Asia/Tehran.
Does daylight saving time affect the Osaka–Tehran difference?
Neither zone observes daylight saving time, so the -5h 30m offset between Osaka and Tehran is fixed all year.
Which other cities share Osaka's time zone?
JST also covers Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka and 1 more.
Which countries use JST, Osaka's zone?
JST is used in Japan.
Is there a day difference between Osaka and Tehran?
Not normally. The -5h 30m gap only pushes the date over the previous day.
What is the time difference between Osaka and Tehran?
Tehran is -5h 30m from Osaka.
What timezone is Osaka in?
Osaka operates on Japan Standard Time (JST), UTC+9. As Japan's second economic center and a manufacturing hub, Osaka shares business hours with Tokyo.
What timezone is Tehran in?
Tehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
What are the business hours in Osaka?
Standard business hours in Osaka are 9:00 AM - 6:00 PM JST.
What are the business hours in Tehran?
Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.
What is the best time to schedule a call between Osaka and Tehran?
The best overlap for a call is when both cities are in business hours. Osaka works 9:00 AM - 6:00 PM JST and Tehran works 8:00 AM - 4:00 PM IRST (-5h 30m difference). Try scheduling during the overlapping window for maximum convenience.
What currencies are used in Osaka and Tehran?
Osaka uses JPY (¥) while Tehran uses IRR (﷼). Check current exchange rates when planning travel or business between these cities.
How do Osaka and Tehran compare in size?
Osaka has a population of approximately 2.8 million (metro: 19 million), while Tehran has approximately 9.4 million (metro: 16.8 million).
What are the major landmarks in Osaka and Tehran?
Osaka is known for Osaka Castle, Dotonbori, Universal Studios Japan. Tehran is famous for Azadi Tower, Golestan Palace, Grand Bazaar.
Do Osaka and Tehran have stock exchanges?
Yes. Osaka has the OSE (Osaka Exchange - derivatives) and Tehran has the TSE (Tehran Stock Exchange). The -5h 30m time difference affects trading hour overlaps between these exchanges.
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 IRST timezone?
Major cities in the IRST timezone include Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
What is the UTC offset for IRST?
Iran Standard Time (IRST) is at UTC+03:30. During daylight saving time, it shifts to IRDT.
What should I know about the IRST timezone?
IRST is one of only a few time zones with a 30-minute offset. Iran observes daylight saving time, switching to IRDT (UTC+04:30).
When is it midnight in Osaka, what time is it in Tehran?
When it is 12:00 AM (midnight) in Osaka (JST), it is -5h 30m later in Tehran (IRST).
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