Time in Indonesia

Map of time zones of Indonesia
Western Indonesia Time UTC offset	UTC+07:00
Central Indonesia Time UTC offset	UTC+08:00
Eastern Indonesia Time UTC offset	UTC+09:00
Adopted	1 January 1988
Time notation	24-hour clock
tz database	Asia/Jakarta · Asia/Pontianak · Asia/Makassar · Asia/Jayapura

The Republic of Indonesia, a country located in Southeast Asia has three time zones. Western Indonesia Time (Waktu Indonesia Barat, WIB) is seven hours ahead (UTC+07:00) of the Coordinated Universal Time (UTC), used in the islands of Sumatra, Java, and the western half of Kalimantan. Central Indonesia Time (Waktu Indonesia Tengah, WITA) is eight hours ahead (UTC+08:00), used in the eastern half of Kalimantan, as well as all of Bali, the Lesser Sunda Islands, and Sulawesi. Eastern Indonesia Time (Waktu Indonesia Timur, WIT) is nine hours ahead (UTC+09:00), used in the Maluku Islands and Western New Guinea.

In 1908, during the Dutch East Indies colonial era, only Java and the Madura Island were initially given time until 1932, when the government utilised UTC+06:30 up to +09:30. In between those changes in 1918, Central Java (UTC+07:20, now defunct) was the basis for time in select locations: for instance, Padang was 7 minutes behind Central Java. The Japanese occupation of the Indies prompted the simplification of time in Indonesia to just UTC+09:00, also known as the Japan Standard Time. The Dutch reoccupied the country following its 1945 independence with UTC+06:00 up to +09:00 established, but it was reverted to the 1932 system after they recognised Indonesia's sovereignty. The current time zone division is a 1988 revision of a 1964 division, with Bali, West Kalimantan, and Central Kalimantan changing sides. Without any significant season changes, the daylight saving time system is not observed anywhere in Indonesia, as is other Southeast Asian countries.

Indonesia is divided into three time zones:

These time zones have existed in their present form since 1 January 1988.^[1]

The first regulation of time was implemented in 1908 at the request of the Staatsspoorwegen Dutch railway company in Java during the time of the Dutch East Indies. The time in Central Java was set at 12 minutes later than the capital, Batavia, which used GMT +7 hours. This regulation, which came into effect on 1 May 1908, applied only to Java and Madura. Time in the rest of the archipelago remained unregulated.^[2][3]

Ten years later, on 22 February 1918, time in Padang, Sumatra was set at 39 minutes ahead of Central Java, while time in Palembang was set at 8 hours and 20 minutes ahead of Greenwich Mean Time. Then, on 1 January 1924, times for various locations were set as follows:^[2][3]

In 1932, the Dutch colonial government through a Governments Besluit dated 27 July published in Staatsblad No. 412, divided the entire colony into six time zones separated by 30 minutes as follows:

During the Japanese occupation of the Dutch East Indies, from 27 March 1942 to 24 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.^[6][3]

When the Dutch returned in 1945, they reimposed three time zones (GMT +6, +7 and +8), with a separate GMT +9 time zone for Dutch New Guinea. Following Dutch recognition of Indonesian sovereignty, a presidential regulation came into effect on 1 May 1950 once again dividing the country into six time zones separated by half an hour. Then, on 1 January 1964, another presidential decree came into effect, imposing the current system of three time zones. The final change came on 1 January 1988 when Bali was moved out of the West Indonesia time zone in to the Central Indonesia timezone, and West and Central Kalimantan were transferred from Central to West Indonesian Time.^[1][2]

On 12 March 2012, Coordinating Minister for the Economy Hatta Rajasa said: "According to research, with a single time zone the country could cut costs by trillions of rupiah."^[7] Two months later, The Jakarta Post reported that a single time zone using UTC+08:00 may start on 28 October 2012.^[8] However, in August, the Jakarta Globe reported that the plan was now on hold.^[9] In January 2013, a deputy minister said the idea had been abandoned after missing two target dates: 17 August (Independence day) and 28 October 2012 (Youth Pledge day).^[10] Later that year, Rajasa claimed that the plan had not been abandoned, although there was no deadline for implementation.^[11]

In the IANA time zone database, Indonesia is given four zones in the file zone.tab: Asia/Jakarta serving Sumatra and Java; Asia/Pontianak serving West and Central Kalimantan; Asia/Makassar serving East Kalimantan, South Kalimantan, the Lesser Sunda Islands, and Sulawesi; and Asia/Jayapura serving the Maluku Islands, Papua, and West Papua. The first two zones use WIB, while the third and last use WITA and WIT, respectively.^[12]

• ASEAN Common Time
• Time in Brunei
• Philippine Standard Time
• Singapore Standard Time
• Time in Malaysia
• Time in Thailand
• Time in South Korea
• Japan Standard Time
• Time in China

• "Hatta: Penyatuan zona waktu tidak batal". okezone.com. Okezone Economy. 9 February 2013. Archived from the original on 4 March 2016. Retrieved 30 March 2018.
• Hendaru Tri Hanggoro (13 March 2013). "Kisah Zona Waktu di Indonesia" [The Story of time Zones in Indonesia]. Historia (in Indonesian). Retrieved 30 May 2023.
• "Indonesia Pernah Ubah 9 Kali Zona Waktu". Viva.co.id. 28 May 2012. Retrieved 9 April 2016.
• Iwan Kurniawan; Raden Jihad Akbar (30 January 2013). "Penyatuan zona waktu Indonesia batal" [Unified Indonesian Time Zone Cancelled]. Viva.co.id (in Indonesian).
• "Keputusan Presiden No. 41 Tahun 1987" (PDF). Keputusan Presiden No. 41 tahun 1987. BAPPENAS. 26 November 1987. Archived from the original (PDF) on 20 April 2016. Retrieved 9 April 2016.
• Post, Peter; Frederick, William H.; Heidebrink, Iris; Sato, Shigeru, eds. (2010). The Encyclopedia of Indonesia in the Pacific War. Handbook of Oriental Studies. Vol. 19. Leiden: Brill. ISBN 978-90-04-16866 4.
• "Results of the 2020 Population Census". BPS.go.id. Statistics Indonesia. September 2020. Retrieved 10 January 2021.
• "Single time zone may begin in late October". TheJakartaPost.com. The Jakarta Post. 26 May 2012b. Retrieved 30 March 2018.
• "Time Zone in Jayapura, Papua, Indonesia". timeanddate.com. Retrieved 9 April 2016.
• "Time Zone Database". IANA. 28 March 2023. Retrieved 31 May 2023.
• Tito Summa Siahaan. "Clock stops on Indonesia's unified time zone". TheJakartaGlobe.com. Jakarta Globe. Archived from the original on 18 October 2012. Retrieved 25 October 2012.
• "Trillions of rupiah could be saved with single time zone: Govt". TheJakartaPost.com. The Jakarta Post. 12 March 2012a. Archived from the original on 20 May 2012. Retrieved 27 May 2012.

• Indonesian Standard Time
• http://www.timetableimages.com/ttimages/kni41.htm