The Indonesian Archipelago geographically stretches across four time zones from UTC+06:00 in Aceh to UTC+09:00 in Papua. However, the Indonesian government recognises only three time zones in its territory, namely:
- Western Indonesia Time (WIB) — seven hours ahead (UTC+07:00) of the Coordinated Universal Time (UTC);
- Central Indonesia Time (WITA) — eight hours ahead (UTC+08:00) of UTC;
- Eastern Indonesia Time (WIT) — nine hours ahead (UTC+09:00) of UTC.
The boundary between the Western and Central time zones was established as a line running north between Java and Bali through the provincial boundaries of West and Central Kalimantan. The border between the Central and Eastern time zones runs north from the eastern tip of Indonesian Timor to the eastern tip of Sulawesi.
Daylight saving time (DST) is no longer observed anywhere in Indonesia.
In Indonesia, the keeping of standard time is divided into three time zones:
These time zones were first observed on 1 January 1988 (according to Presidential Decree 41/1987). Prior to that date, West and Central Kalimantan used WITA, while Bali belonged to WIB (since 29 November 1963).
Standardised Time Zone (Indonesia 1932)
|time zone||in Dutch||UTC
|Northern Sumatra Time||Nord-Sumatra tijd||UTC+06:30||Aceh, Padang, and Medan.|
|Southern Sumatra Time||Zuid-Sumatra tijd||UTC+07:00||Bengkulu, Palembang, and Lampung.|
|Java Time||Java tijd||UTC+07:30||Java, Bali, Madura and Kalimantan.|
|Celebes Time||Celebes tijd||UTC+08:00||Sulawesi and Lesser Sunda Islands.|
|Moluccan Time||Molukken tijd||UTC+08:30||Ternate, Namlea, Ambon, and Banda.|
|New Guinea||Nieuw-Guinea tijd||UTC+09:00||West Irian. It observed during 1 November 1932 to 31 August 1944.|
|Dutch New Guinea Time||Nederlandse Nieuw-Guinea tijd||UTC+09:30||West Irian during named Dutch New Guinea because Netherlands still hold West Irian. It observed from 1 September 1944 to 31 December 1963.|
Western parts of Indonesia observed 30 minute daylight saving time (DST) from 1 November 1932 to 23 March 1942, and from 23 September 1945 to 1 January 1964 (except from 1 May 1948 to 1 May 1950, which observed 1 hour daylight saving time instead). West and Central Borneo also observed 1 hour DST from 1 January 1964 to 1 January 1988. Eastern Indonesia observed 30 minute DST from 1 September 1944 until 1 January 1964. Furthermore, 20 minute daylight saving time was observed in Java and Sumatra from 1 January 1924 to 1 November 1932.
From 23 March 1942 to 23 September 1945, both western and central parts of Indonesia used Japan Standard Time (JST) (UTC+09:00) for the sake of the effectiveness of Japanese military operations in Indonesia This meant that western parts of Indonesia observed 2 hour daylight saving time, and central parts of Indonesia observed 1 hour daylight saving time during the period of Japanese occupation 1942 to 1945.
Proposal for a single time zone
|12 March 2012||Coordinating Minister for the Economy Hatta Rajasa is reported to have said: "According to research, with a single time zone the country could cut costs by trillions of rupiah,"|
|26 May 2012||The Jakarta Post reported on 26 May 2012 that a single time zone using UTC+08:00 may start on 28 October 2012.|
|30 July 2012||Reported on 30 July 2012 as still on the agenda|
|31 August 2012||Jakarta Globe reported on 31 August 2012 that a single time zone is now put on hold. The Indonesian Economic Development Committee (KP3EI) cited that they will need at least 3 months to communicate and plan for the change. Hence this could happen in 2013.|
|30 January 2013||A deputy minister said the idea has been abandoned after missed two target dates: 17 August (Independence day) and 28 October 2012 (Youth Pledge day)|
|9 September 2013||Then the minister said that it's not abandoned, only without any definite date|
IANA time zone database
- ASEAN Common Time
- Philippine Standard Time
- Singapore Standard Time
- Time in Malaysia
- Time in Thailand
- Time in South Korea
- Japan Standard Time
- Time in China
- "Result of the 2020 Population Census". BPS.go.id. Statistics Indonesia. September 2020. Retrieved 10 January 2021.
- Soeharto (26 November 1987). "Keputusan Presiden No. 41 Tahun 1987" (PDF). Keputusan Presiden No. 41 tahun 1987. BAPPENAS. Archived from the original (PDF) on 20 April 2016. Retrieved 9 April 2016.
- "Indonesia Pernah Ubah 9 Kali Zona Waktu". Viva.co.id. 28 May 2012. Retrieved 9 April 2016.
- "Garuda Indonesian Airways". TimetableImages.com. 1963. Retrieved 4 March 2019.
- "Time Zone in Jayapura, Papua, Indonesia". timeanddate.com. Retrieved 9 April 2016.
- "Eggert/Tz". GitHub. 10 February 2022.
- "Time zone and clock changes in Jakarta, Jakarta Special Capital Region, Indonesia". timeanddate.com. Retrieved 30 March 2018.
- "Trillions of rupiah could be saved with single time zone: Govt". TheJakartaPost.com. The Jakarta Post. 12 March 2012. Archived from the original on 20 May 2012. Retrieved 27 May 2012.
- "Single time zone may begin in late October". TheJakartaPost.com. The Jakarta Post. 26 May 2012. Retrieved 30 March 2018.
- "Indonesia to implement single time zone". KhabarSouthEastAsia.com. 30 July 2012. Archived from the original on 31 July 2012. Retrieved 30 March 2018.
- "Clock stops on Indonesia's unified time zone". TheJakartaGlobe.com. Jakarta Globe. Archived from the original on 18 October 2012. Retrieved 25 October 2012.
- "Penyatuan zona waktu Indonesia batal". bisnis.news.viva.co.id (in Indonesian).
- "Hatta: Penyatuan zona waktu tidak batal". okezone.com. Okezone Economy. 9 February 2013. Retrieved 30 March 2018.