What is the time difference between Chatham Islands and London?

London is 11 hours 45 minutes behind Chatham Islands. 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 London from Chatham Islands?

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 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.

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.

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

It is 00:15 in London, 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 Chatham Islands and London use?

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

Convert Chatham Islands time to London time

London is 11 hours 45 minutes behind Chatham Islands right now, so midday in Chatham Islands lands in the small hours in London.

Convert a time

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Date

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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 Chatham Islands, across for London.

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

Daylight saving time

Both cities change their clocks, but not necessarily on the same date — which is why the difference between them shifts for a few weeks each year.

Chatham Islands

Observes daylight saving time

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

London

Observes daylight saving time

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

When you can actually talk

There is no hour where both cities are inside a 09:00–18:00 working day. Someone has to move — the nearest workable windows are below.

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

Reference

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

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

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

Common questions

What is the time difference between Chatham Islands and London?: London is 11 hours 45 minutes behind Chatham Islands. 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 London from Chatham Islands?: 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 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.
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.
If it is midday in Chatham Islands, what time is it in London?: It is 00:15 in London, 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 Chatham Islands and London use?: Chatham Islands uses Pacific/Chatham, currently UTC+12:45 (CHAST), and London uses Europe/London, currently UTC+1 (BST). Those identifiers are the ones to use in code — abbreviations are ambiguous and offsets change.