Time Zones Currently Being Used in Indonesia
Time Zone Currently Being Used in Vietnam
Vietnam observes Indochina Time all year. There are no Daylight Saving Time clock changes.
Single Time Zone Considered in 2012
In 2012, Indonesian lawmakers considered merging the three time zones to UTC+8 (Central Indonesian Time). It would have lined up Indonesia's time zone with trading partners in other countries like China, Singapore, and Western Australia. The Indonesian government later postponed the measure.
Indonesian time zones follow provincial boundaries. Western Borneo consists of the provinces of Kalimantan Barat and Kalimantan Tengah; Eastern Borneo is Kalimantan Selatan and Kalimantan Timur.
Source: This information was adapted from the tz database.
1988-01-01 00:00 Western Borneo switched from Asia/Ujung_Pandang to Asia/Jakarta zone.
The following names and abbreviations are standard in Indonesia.
More formally, the names can be written "Waktu Indonesia Bagian Barat", etc. ("bagian" = "region").
The following names and abbreviations for Indonesian time zones come from the tz database. They were created by a contributor. Don't assume that these names, or anything like them, have ever been used officially in Indonesia. The western zone was called Jakarta Mean Time (JMT) from 1924 to 1932, and Java Time (JAVT) thereafter. The central zone was called Macassar Mean Time (MMT) from 1932 to 1942, and Borneo Time (BORT) thereafter. (Note: the name of the city of Macassar was changed to Ujung Pandang around 1970.) The eastern zone was called Jayapura Time (JAYT) from 1944 onward. UTC+9, as used during World War II, was called JST. UTC+9:30, as used in the eastern zone from 1944 to 1963, was called CST. There is no indication what this stood for.
Reference: Time Genie
Three Indonesia Time Zones
The Indonesian archipelago stretches from 94°45′E to 141°05′E longitude and spans three time zones from UTC+7 in the west, via a central UTC+8, to UTC+9 in the east.
Six thousand of Indonesia's more than 17,000 islands are inhabited. Western Indonesian Time (WIB), including the densely populated island of Java and the capital Jakarta, is the time zone that a majority of the population use. Central Indonesian Time (WITA) is used in the central region, including the holiday island of Bali. Eastern Indonesian Time (WIT) is used in the east, including West Papua on the Indonesian part of the island New Guinea.
