What is the time difference between London and Chatham Islands?

Chatham Islands is 11 hours 45 minutes ahead of London. That figure is current — it changes by an hour when either city starts or ends daylight saving, and the exact dates are listed above.

When is the best time to call Chatham Islands from London?

There is no time inside normal working hours in both cities, so someone has to take the call outside them. The nearest workable windows are listed above — pick one and alternate who gets the awkward slot.

Does London observe daylight saving time?

Yes. London runs on UTC+0 in winter and UTC+1 in summer. The next change is on 2026-10-25, when clocks go back by 60 minutes.

Does Chatham Islands observe daylight saving time?

Yes. Chatham Islands runs on UTC+12:45 in winter and UTC+13:45 in summer. The next change is on 2026-09-27, when clocks go forward by 60 minutes.

If it is midday in London, what time is it in Chatham Islands?

It is 23:45 in Chatham Islands, on the same calendar date. That holds for the current offsets; it shifts by an hour around the daylight saving dates listed above.

Which time zones do London and Chatham Islands use?

London uses Europe/London, currently UTC+1 (BST), and Chatham Islands uses Pacific/Chatham, currently UTC+12:45 (CHAST). Those identifiers are the ones to use in code — abbreviations are ambiguous and offsets change.

Convert London time to Chatham Islands time

Right now Chatham Islands runs 11 hours 45 minutes ahead of London. That gap is not fixed: it moves when either city changes its clocks.

Convert a time

From

Date

Time

Converted time

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The converter needs JavaScript to run. Everything below — offsets, daylight saving dates and the hour-by-hour table — is part of the page and works without it.

Hour by hour

The whole day mapped across: read down the left for London, across for Chatham Islands.

London	Chatham Islands
00:00	11:45
01:00	12:45
02:00	13:45
03:00	14:45
04:00	15:45
05:00	16:45
06:00	17:45
07:00	18:45
08:00	19:45
09:00	20:45
10:00	21:45
11:00	22:45
12:00	23:45
13:00	00:45next day
14:00	01:45next day
15:00	02:45next day
16:00	03:45next day
17:00	04:45next day
18:00	05:45next day
19:00	06:45next day
20:00	07:45next day
21:00	08:45next day
22:00	09:45next day
23:00	10:45next day

Daylight saving time

London and Chatham Islands both observe daylight saving. Where their change dates differ, so does the gap between them for the weeks in between.

London

Observes daylight saving time

Standard: UTC+0
Daylight: UTC+1
Next change: 2026-10-25 −60m

Chatham Islands

Observes daylight saving time

Standard: UTC+12:45
Daylight: UTC+13:45
Next change: 2026-09-27 +60m

When you can actually talk

A standard working day in London and one in Chatham Islands do not overlap at all. Any call between them is early for one side or late for the other.

London 01:00–06:15Chatham Islands 12:45–18:00
London 09:00–18:00Chatham Islands 20:45–05:45

Reference

The underlying data, in case you need to put it in a calendar invitation or a configuration file.

	London	Chatham Islands
IANA zone	Europe/London	Pacific/Chatham
Abbreviation	BST	CHAST
Standard offset	UTC+0	UTC+12:45
Daylight offset	UTC+1	UTC+13:45
Clock changes this year	2	2
Country	United Kingdom	New Zealand

Example, not the current time. Live times appear once the page loads.

Common questions

What is the time difference between London and Chatham Islands?: Chatham Islands is 11 hours 45 minutes ahead of London. That figure is current — it changes by an hour when either city starts or ends daylight saving, and the exact dates are listed above.
When is the best time to call Chatham Islands from London?: There is no time inside normal working hours in both cities, so someone has to take the call outside them. The nearest workable windows are listed above — pick one and alternate who gets the awkward slot.
Does London observe daylight saving time?: Yes. London runs on UTC+0 in winter and UTC+1 in summer. The next change is on 2026-10-25, when clocks go back by 60 minutes.
Does Chatham Islands observe daylight saving time?: Yes. Chatham Islands runs on UTC+12:45 in winter and UTC+13:45 in summer. The next change is on 2026-09-27, when clocks go forward by 60 minutes.
If it is midday in London, what time is it in Chatham Islands?: It is 23:45 in Chatham Islands, on the same calendar date. That holds for the current offsets; it shifts by an hour around the daylight saving dates listed above.
Which time zones do London and Chatham Islands use?: London uses Europe/London, currently UTC+1 (BST), and Chatham Islands uses Pacific/Chatham, currently UTC+12:45 (CHAST). Those identifiers are the ones to use in code — abbreviations are ambiguous and offsets change.