Connect to O365 via Powershell
We will have to define the Language and Timezone first.
get-mailbox | Set-MailboxRegionalConfiguration -Language -TimeZone
| 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 |
| Basque | 1069 |
| Bulgarian | 1026 |
| Catalan | 1027 |
| 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 |
| Croatian | 1050 |
| Czech | 1029 |
| Danish | 1030 |
| 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 |
| Estonian | 1061 |
| Filipino (Philippines) | 1124 |
| Finnish | 1035 |
| 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 |
| Greek | 1032 |
| Hebrew | 1037 |
| Hindi | 1081 |
| Hungarian | 1038 |
| Icelandic | 1039 |
| Indonesian | 1057 |
| Italian (Italy) | 1040 |
| Italian (Switzerland) | 2064 |
| Japanese | 1041 |
| Kazakh | 1087 |
| Korean | 1042 |
| Latvian | 1062 |
| Lithuanian | 1063 |
| Malay | 1086 |
| Norwegian (Bokmål) | 1044 |
| Persian | 1065 |
| Polish | 1045 |
| Portuguese (Brazil) | 1046 |
| Portuguese (Portugal) | 2070 |
| Romanian | 1048 |
| Russian | 1049 |
| Serbian (Cyrillic) | 3098 |
| Serbian (Latin) | 2074 |
| Slovak | 1051 |
| Slovenian | 1060 |
| 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 |
| Thai | 1054 |
| Turkish | 1055 |
| Ukrainian | 1058 |
| Urdu | 1056 |
| Vietnamese | 1066 |
For the timezone, select the middle value:
| Index | Name of Time Zone | Time |
|---|---|---|
| 0 | Dateline Standard Time | (GMT-12:00) International Date Line West |
| 1 | Samoa Standard Time | (GMT-11:00) Midway Island, Samoa |
| 2 | Hawaiian Standard Time | (GMT-10:00) Hawaii |
| 3 | Alaskan Standard Time | (GMT-09:00) Alaska |
| 4 | Pacific Standard Time | (GMT-08:00) Pacific Time (US and Canada); Tijuana |
| 10 | Mountain Standard Time | (GMT-07:00) Mountain Time (US and Canada) |
| 13 | Mexico Standard Time 2 | (GMT-07:00) Chihuahua, La Paz, Mazatlan |
| 15 | U.S. Mountain Standard Time | (GMT-07:00) Arizona |
| 20 | Central Standard Time | (GMT-06:00) Central Time (US and Canada |
| 25 | Canada Central Standard Time | (GMT-06:00) Saskatchewan |
| 30 | Mexico Standard Time | (GMT-06:00) Guadalajara, Mexico City, Monterrey |
| 33 | Central America Standard Time | (GMT-06:00) Central America |
| 35 | Eastern Standard Time | (GMT-05:00) Eastern Time (US and Canada) |
| 40 | U.S. Eastern Standard Time | (GMT-05:00) Indiana (East) |
| 45 | S.A. Pacific Standard Time | (GMT-05:00) Bogota, Lima, Quito |
| 50 | Atlantic Standard Time | (GMT-04:00) Atlantic Time (Canada) |
| 55 | S.A. Western Standard Time | (GMT-04:00) Caracas, La Paz |
| 56 | Pacific S.A. Standard Time | (GMT-04:00) Santiago |
| 60 | Newfoundland and Labrador Standard Time | (GMT-03:30) Newfoundland and Labrador |
| 65 | E. South America Standard Time | (GMT-03:00) Brasilia |
| 70 | S.A. Eastern Standard Time | (GMT-03:00) Buenos Aires, Georgetown |
| 73 | Greenland Standard Time | (GMT-03:00) Greenland |
| 75 | Mid-Atlantic Standard Time | (GMT-02:00) Mid-Atlantic |
| 80 | Azores Standard Time | (GMT-01:00) Azores |
| 83 | Cape Verde Standard Time | (GMT-01:00) Cape Verde Islands |
| 85 | GMT Standard Time | (GMT) Greenwich Mean Time: Dublin, Edinburgh, Lisbon, London |
| 90 | Greenwich Standard Time | (GMT) Casablanca, Monrovia |
| 95 | Central Europe Standard Time | (GMT+01:00) Belgrade, Bratislava, Budapest, Ljubljana, Prague |
| 100 | Central European Standard Time | (GMT+01:00) Sarajevo, Skopje, Warsaw, Zagreb |
| 105 | Romance Standard Time | (GMT+01:00) Brussels, Copenhagen, Madrid, Paris |
| 110 | W. Europe Standard Time | (GMT+01:00) Amsterdam, Berlin, Bern, Rome, Stockholm, Vienna |
| 113 | W. Central Africa Standard Time | (GMT+01:00) West Central Africa |
| 115 | E. Europe Standard Time | (GMT+02:00) Bucharest |
| 120 | Egypt Standard Time | (GMT+02:00) Cairo |
| 125 | FLE Standard Time | (GMT+02:00) Helsinki, Kiev, Riga, Sofia, Tallinn, Vilnius |
| 130 | GTB Standard Time | (GMT+02:00) Athens, Istanbul, Minsk |
| 135 | Israel Standard Time | (GMT+02:00) Jerusalem |
| 140 | South Africa Standard Time | (GMT+02:00) Harare, Pretoria |
| 145 | Russian Standard Time | (GMT+03:00) Moscow, St. Petersburg, Volgograd |
| 150 | Arab Standard Time | (GMT+03:00) Kuwait, Riyadh |
| 155 | E. Africa Standard Time | (GMT+03:00) Nairobi |
| 158 | Arabic Standard Time | (GMT+03:00) Baghdad |
| 160 | Iran Standard Time | (GMT+03:30) Tehran |
| 165 | Arabian Standard Time | (GMT+04:00) Abu Dhabi, Muscat |
| 170 | Caucasus Standard Time | (GMT+04:00) Baku, Tbilisi, Yerevan |
| 175 | Transitional Islamic State of Afghanistan Standard Time | (GMT+04:30) Kabul |
| 180 | Ekaterinburg Standard Time | (GMT+05:00) Ekaterinburg |
| 185 | West Asia Standard Time | (GMT+05:00) Islamabad, Karachi, Tashkent |
| 190 | India Standard Time | (GMT+05:30) Chennai, Kolkata, Mumbai, New Delhi |
| 193 | Nepal Standard Time | (GMT+05:45) Kathmandu |
| 195 | Central Asia Standard Time | (GMT+06:00) Astana, Dhaka |
| 200 | Sri Lanka Standard Time | (GMT+06:00) Sri Jayawardenepura |
| 201 | N. Central Asia Standard Time | (GMT+06:00) Almaty, Novosibirsk |
| 203 | Myanmar Standard Time | (GMT+06:30) Yangon Rangoon |
| 205 | S.E. Asia Standard Time | (GMT+07:00) Bangkok, Hanoi, Jakarta |
| 207 | North Asia Standard Time | (GMT+07:00) Krasnoyarsk |
| 210 | China Standard Time | (GMT+08:00) Beijing, Chongqing, Hong Kong SAR, Urumqi |
| 215 | Singapore Standard Time | (GMT+08:00) Kuala Lumpur, Singapore |
| 220 | Taipei Standard Time | (GMT+08:00) Taipei |
| 225 | W. Australia Standard Time | (GMT+08:00) Perth |
| 227 | North Asia East Standard Time | (GMT+08:00) Irkutsk, Ulaanbaatar |
| 230 | Korea Standard Time | (GMT+09:00) Seoul |
| 235 | Tokyo Standard Time | (GMT+09:00) Osaka, Sapporo, Tokyo |
| 240 | Yakutsk Standard Time | (GMT+09:00) Yakutsk |
| 245 | A.U.S. Central Standard Time | (GMT+09:30) Darwin |
| 250 | Cen. Australia Standard Time | (GMT+09:30) Adelaide |
| 255 | A.U.S. Eastern Standard Time | (GMT+10:00) Canberra, Melbourne, Sydney |
| 260 | E. Australia Standard Time | (GMT+10:00) Brisbane |
| 265 | Tasmania Standard Time | (GMT+10:00) Hobart |
| 270 | Vladivostok Standard Time | (GMT+10:00) Vladivostok |
| 275 | West Pacific Standard Time | (GMT+10:00) Guam, Port Moresby |
| 280 | Central Pacific Standard Time | (GMT+11:00) Magadan, Solomon Islands, New Caledonia |
| 285 | Fiji Islands Standard Time | (GMT+12:00) Fiji Islands, Kamchatka, Marshall Islands |
| 290 | New Zealand Standard Time | (GMT+12:00) Auckland, Wellington |
| 300 | Tonga Standard Time | (GMT+13:00) Nuku’alofa |
To apply the desired language and timezone for all the mailboxes on your tenant, use the following syntax:
get-mailbox | Set-MailboxRegionalConfiguration -Language 1033 -TimeZone "S.A. Eastern Standard Time"