I recently came across a question in the Office 365 Forums asking how one can set the Language and Time Zone for all users in Office 365.

For this we need to use the Set-MailboxRegionalConfiguration cmdlet in PowerShell. Once we’ve connected to Office 365 using Powershell, we only need to run one cmdlet.

get-mailbox | Set-MailboxRegionalConfiguration -Language  -TimeZone

The Language ID is a number that corresponds to the correct language type. The following table shows you which number corresponds to which language.

Language (Locale)Code
Arabic (Algeria)5121
Arabic (Bahrain)15361
Arabic (Egypt)3073
Arabic (Iraq)2049
Arabic (Jordan)11265
Arabic (Kuwait)13313
Arabic (Lebanon)12289
Arabic (Libya)4097
Arabic (Morocco)6145
Arabic (Oman)8193
Arabic (Qatar)16385
Arabic (Saudi Arabia)1025
Arabic (Syria)10241
Arabic (Tunisia)7169
Arabic (U.A.E.)14337
Arabic (Yemen)9217
Chinese (Hong Kong S.A.R)3076
Chinese (Macau S.A.R)5124
Chinese (People’s Republic of China)2052
Chinese (Singapore)4100
Chinese (Taiwan)1028
Dutch (Belgium)2067
Dutch (Netherlands)1043
English (Australia)3081
English (Belize)10249
English (Canada)4105
English (Caribbean)9225
English (Ireland)6153
English (Jamaica)8201
English (New Zealand)5129
English (Republic of the Philippines)13321
English (South Africa)7177
English (Trinidad)11273
English (United Kingdom)2057
English (United States)1033
English (Zimbabwe)12297
Filipino (Philippines)1124
French (Belgium)2060
French (Canada)3084
French (France)1036
French (Luxembourg)5132
French (Principality of Monaco)6156
French (Switzerland)4108
German (Austria)3079
German (Germany)1031
German (Liechtenstein)5127
German (Luxembourg)4103
German (Switzerland)2055
Italian (Italy)1040
Italian (Switzerland)2064
Norwegian (Bokmål)1044
Portuguese (Brazil)1046
Portuguese (Portugal)2070
Serbian (Cyrillic)3098
Serbian (Latin)2074
Spanish (Argentina)11274
Spanish (Bolivia)16394
Spanish (Chile)13322
Spanish (Colombia)9226
Spanish (Costa Rica)5130
Spanish (Dominican Republic)7178
Spanish (Ecuador)12298
Spanish (El Salvador)17418
Spanish (Guatemala)4106
Spanish (Honduras)18442
Spanish (Mexico)2058
Spanish (Nicaragua)19466
Spanish (Panama)6154
Spanish (Paraguay)15370
Spanish (Peru)10250
Spanish (Puerto Rico)20490
Spanish (International Sort)3082
Spanish (Traditional Sort)1034
Spanish (Uruguay)14346
Spanish (Venezuela)8202
Swedish (Finland)2077
Swedish (Sweden)1053

The TimeZone consists of a String representing the time zone.  Use the value from the middle column of the table below:

IndexName of Time ZoneTime
000Dateline Standard Time(GMT-12:00) International Date Line West
001Samoa Standard Time(GMT-11:00) Midway Island, Samoa
002Hawaiian Standard Time(GMT-10:00) Hawaii
003Alaskan Standard Time(GMT-09:00) Alaska
004Pacific Standard Time(GMT-08:00) Pacific Time (US and Canada); Tijuana
010Mountain Standard Time(GMT-07:00) Mountain Time (US and Canada)
013Mexico Standard Time 2(GMT-07:00) Chihuahua, La Paz, Mazatlan
015U.S. Mountain Standard Time(GMT-07:00) Arizona
020Central Standard Time(GMT-06:00) Central Time (US and Canada
025Canada Central Standard Time(GMT-06:00) Saskatchewan
030Mexico Standard Time(GMT-06:00) Guadalajara, Mexico City, Monterrey
033Central America Standard Time(GMT-06:00) Central America
035Eastern Standard Time(GMT-05:00) Eastern Time (US and Canada)
040U.S. Eastern Standard Time(GMT-05:00) Indiana (East)
045S.A. Pacific Standard Time(GMT-05:00) Bogota, Lima, Quito
050Atlantic Standard Time(GMT-04:00) Atlantic Time (Canada)
055S.A. Western Standard Time(GMT-04:00) Caracas, La Paz
056Pacific S.A. Standard Time(GMT-04:00) Santiago
060Newfoundland and Labrador Standard Time(GMT-03:30) Newfoundland and Labrador
065E. South America Standard Time(GMT-03:00) Brasilia
070S.A. Eastern Standard Time(GMT-03:00) Buenos Aires, Georgetown
073Greenland Standard Time(GMT-03:00) Greenland
075Mid-Atlantic Standard Time(GMT-02:00) Mid-Atlantic
080Azores Standard Time(GMT-01:00) Azores
083Cape Verde Standard Time(GMT-01:00) Cape Verde Islands
085GMT Standard Time(GMT) Greenwich Mean Time: Dublin, Edinburgh, Lisbon, London
090Greenwich Standard Time(GMT) Casablanca, Monrovia
095Central Europe Standard Time(GMT+01:00) Belgrade, Bratislava, Budapest, Ljubljana, Prague
100Central European Standard Time(GMT+01:00) Sarajevo, Skopje, Warsaw, Zagreb
105Romance Standard Time(GMT+01:00) Brussels, Copenhagen, Madrid, Paris
110W. Europe Standard Time(GMT+01:00) Amsterdam, Berlin, Bern, Rome, Stockholm, Vienna
113W. Central Africa Standard Time(GMT+01:00) West Central Africa
115E. Europe Standard Time(GMT+02:00) Bucharest
120Egypt Standard Time(GMT+02:00) Cairo
125FLE Standard Time(GMT+02:00) Helsinki, Kiev, Riga, Sofia, Tallinn, Vilnius
130GTB Standard Time(GMT+02:00) Athens, Istanbul, Minsk
135Israel Standard Time(GMT+02:00) Jerusalem
140South Africa Standard Time(GMT+02:00) Harare, Pretoria
145Russian Standard Time(GMT+03:00) Moscow, St. Petersburg, Volgograd
150Arab Standard Time(GMT+03:00) Kuwait, Riyadh
155E. Africa Standard Time(GMT+03:00) Nairobi
158Arabic Standard Time(GMT+03:00) Baghdad
160Iran Standard Time(GMT+03:30) Tehran
165Arabian Standard Time(GMT+04:00) Abu Dhabi, Muscat
170Caucasus Standard Time(GMT+04:00) Baku, Tbilisi, Yerevan
175Transitional Islamic State of Afghanistan Standard Time(GMT+04:30) Kabul
180Ekaterinburg Standard Time(GMT+05:00) Ekaterinburg
185West Asia Standard Time(GMT+05:00) Islamabad, Karachi, Tashkent
190India Standard Time(GMT+05:30) Chennai, Kolkata, Mumbai, New Delhi
193Nepal Standard Time(GMT+05:45) Kathmandu
195Central Asia Standard Time(GMT+06:00) Astana, Dhaka
200Sri Lanka Standard Time(GMT+06:00) Sri Jayawardenepura
201N. Central Asia Standard Time(GMT+06:00) Almaty, Novosibirsk
203Myanmar Standard Time(GMT+06:30) Yangon Rangoon
205S.E. Asia Standard Time(GMT+07:00) Bangkok, Hanoi, Jakarta
207North Asia Standard Time(GMT+07:00) Krasnoyarsk
210China Standard Time(GMT+08:00) Beijing, Chongqing, Hong Kong SAR, Urumqi
215Singapore Standard Time(GMT+08:00) Kuala Lumpur, Singapore
220Taipei Standard Time(GMT+08:00) Taipei
225W. Australia Standard Time(GMT+08:00) Perth
227North Asia East Standard Time(GMT+08:00) Irkutsk, Ulaanbaatar
230Korea Standard Time(GMT+09:00) Seoul
235Tokyo Standard Time(GMT+09:00) Osaka, Sapporo, Tokyo
240Yakutsk Standard Time(GMT+09:00) Yakutsk
245A.U.S. Central Standard Time(GMT+09:30) Darwin
250Cen. Australia Standard Time(GMT+09:30) Adelaide
255A.U.S. Eastern Standard Time(GMT+10:00) Canberra, Melbourne, Sydney
260E. Australia Standard Time(GMT+10:00) Brisbane
265Tasmania Standard Time(GMT+10:00) Hobart
270Vladivostok Standard Time(GMT+10:00) Vladivostok
275West Pacific Standard Time(GMT+10:00) Guam, Port Moresby
280Central Pacific Standard Time(GMT+11:00) Magadan, Solomon Islands, New Caledonia
285Fiji Islands Standard Time(GMT+12:00) Fiji Islands, Kamchatka, Marshall Islands
290New Zealand Standard Time(GMT+12:00) Auckland, Wellington
300Tonga Standard Time(GMT+13:00) Nuku’alofa

In the Example below we will set all mailboxes in our Office 365 Tenant to the Language English (UK) and the GMT Time Zone.

PS C:\Users\burns_000\Desktop> get-mailbox | Set-MailboxRegionalConfiguration -Language 3082 -TimeZone "Romance Standard Time"