Ideal time to call British Indian Ocean Territory (+246)
BIOT (Diego Garcia) runs on Indian Ocean Time — UTC+6. Authorized defense and government contacts at Diego Garcia are reachable during military operational hours.
IOT (UTC+6), at a glance.
The British Indian Ocean Territory (Diego Garcia) observes Indian Ocean Time at UTC+6. The military base operates on this time zone for all administrative functions.
BIOT against the world's hubs.
Diego Garcia is 6 h ahead of London, in sync with Dhaka, and 11 h ahead of New York. London-based MoD contacts reach Diego Garcia 6 AM–2 PM London time (12 PM–8 PM Diego Garcia time).
Understanding the time difference between the United States and British Indian Ocean Territory
Time zone differences across other major countries
Why timing matters for authorized BIOT calls.
Diego Garcia's defense contractor offices and government liaison desks operate on strict military schedules. The 8 AM–4 PM IOT window is the official administrative hours for US-UK joint operations contacts.
The authorized windows to reach BIOT.
8 AM–4 PM IOT for authorized government and defense contractors. From London, that's 2 AM–10 AM — contact the UK MoD liaison in London during UK business hours to route calls to Diego Garcia.
British Indian Ocean Territory runs at +06:00
The zone is Indian/Chagos. Every window on this page is worked out from that offset rather than a rule of thumb, so the times shown are the ones that actually apply to British Indian Ocean Territory.
No daylight saving
British Indian Ocean Territory stays on +06:00 all year. The windows below only move when the caller's own country changes its clocks, not when British Indian Ocean Territory does.
Shared hours with 3 of 5 markets
Callers in London, Mumbai, Sydney share part of the working day with British Indian Ocean Territory. The table above gives the exact intersection for each.
Where the gap is too wide
There is no 9-to-5 overlap with New York, Los Angeles. Calling British Indian Ocean Territory from those cities means someone is working outside normal hours — worth saying so when you book the call.
How to call the British Indian Ocean Territory using the +246 code.
Dial +246 then the five-digit number. Access is restricted to authorized defense and government channels. Ringflow routes via approved military corridors.
Number anatomy
Dial exit code
Press + on mobile or 00 from most landlines. This opens an international line.
Enter +246
British Indian Ocean Territory's international code. Every call to British Indian Ocean Territory must start with +246.
Area prefix
Add the local area or mobile network code — always drop any leading zero used for domestic calls.
Full number
Dial the remaining subscriber digits. Your number is now correctly formatted for international routing.
Best time to call — every country.
Jump to any country's best-time-to-call guide. Search by name, ISO or dial prefix.
Reach BIOT on authorized defense and government routes.
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When your working day overlaps British Indian Ocean Territory
Callers in London, Mumbai and Sydney share part of the working day with British Indian Ocean Territory. There is no shared working window with New York and Los Angeles.
| Calling from | British Indian Ocean Territory is | Call at (your time) | Which is (their time) |
|---|---|---|---|
| New York | 11h ahead | No shared working hours — you would need to call outside 9am-5pm | |
| Los Angeles | 14h ahead | No shared working hours — you would need to call outside 9am-5pm | |
| London | 6h ahead | 9:00 AM – 11:00 AM | 3:00 PM – 5:00 PM |
| Mumbai | 30m ahead | 9:00 AM – 4:30 PM | 9:30 AM – 5:00 PM |
| Sydney | 5h behind | 2:00 PM – 5:00 PM | 9:00 AM – 12:00 PM |
Windows are the intersection of a 9am-5pm working day in each place, using British Indian Ocean Territory'sstandard-time offset of +06:00. British Indian Ocean Territory does not observe daylight saving, so these windows hold all year — though they shift when the caller's own country changes its clocks.
FAQ
Calling British Indian Ocean Territory, answered.
Time zone, daylight saving and dialling questions for British Indian Ocean Territory (+246).