 Map of time zones of Indonesia | |
| Western Indonesia TimeUTC 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 |
TheRepublic of Indonesia, a country located inSoutheast Asia has threetime zones.Western Indonesia Time (Waktu Indonesia Barat,WIB) is seven hours ahead (UTC+07:00) of theCoordinated Universal Time (UTC), used in the islands ofSumatra,Java, and the western half ofKalimantan.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 ofBali, theLesser Sunda Islands, andSulawesi.Eastern Indonesia Time (Waktu Indonesia Timur,WIT) is nine hours ahead (UTC+09:00), used in theMaluku Islands andWestern New Guinea. About 80% of the Indonesian population live in WIB (UTC+07:00).
In 1908, during theDutch East Indies colonial era, only Java and theMadura Island were initially given time until 1932, when the government utilisedUTC+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. TheJapanese occupation of the Indies prompted the simplification of time in Indonesia to justUTC+09:00, also known as theJapan Standard Time. The Dutch reoccupied the country following its 1945 independence withUTC+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, andCentral Kalimantan changing sides. Without any significant season changes, thedaylight saving time system is not observed anywhere in Indonesia, as is other Southeast Asian countries.
Indonesia is divided into three time zones:
| Time zone name | Original name | UTC offset | WIB offset | Provinces covered |
|---|---|---|---|---|
| Western Indonesia Time (WIB) | Waktu Indonesia Barat | UTC+07:00 | WIB+/-0h | Aceh,Bengkulu,Jambi,Lampung,North Sumatra,Riau,South Sumatra,West Sumatra,Riau Islands,Bangka Belitung Islands,Banten,Jakarta,West Java,Central Java,Special Region of Yogyakarta,East Java,West Kalimantan, andCentral Kalimantan |
| Central Indonesia Time (WITA) | Waktu Indonesia Tengah | UTC+08:00 | WIB+1h | South Kalimantan,East Kalimantan,North Kalimantan,North Sulawesi,GorontaloCentral Sulawesi,West Sulawesi,South Sulawesi,Southeast Sulawesi,Bali,West Nusa Tenggara, andEast Nusa Tenggara |
| Eastern Indonesia Time (WIT) | Waktu Indonesia Timur | UTC+09:00 | WIB+2h | Maluku,North Maluku,Central Papua,Highland Papua,Papua,South Papua,Southwest Papua andWest Papua |
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 theStaatsspoorwegen Dutch railway company inJava during the time of theDutch East Indies. The time inCentral 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 andMadura. Time in the rest of the archipelago remained unregulated.[2][3]
Ten years later, on 22 February 1918, time inPadang, Sumatra was set at 39 minutes ahead of Central Java, while time inPalembang was set at 8 hours and 20 minutes ahead ofGreenwich Mean Time. Then, on 1 January 1924, times for various locations were set as follows:[2][3]
| Location | Time |
|---|---|
| Central Java | GMT +7:20 |
| Tapanoeli Residency | Central Java −45 min (GMT +6:35) |
| Padang | Central Java −7 min (GMT +7:13) |
| Bali andLombok | Central Java +22 min (GMT +7:44) |
| Makassar | Central Java +38 min (GMT +7:58) |
In 1932, the Dutch colonial government through aGovernments Besluit dated 27 July published inStaatsblad No. 412, divided the entire colony into six time zones separated by 30 minutes as follows:
| Time zone | inDutch | UTC offset | locations |
|---|---|---|---|
| Northern Sumatra Time | Noord-Sumatra tijd | UTC+06:30 | Aceh,Padang, andMedan. |
| Southern Sumatra Time | Zuid-Sumatra tijd | UTC+07:00 | Bengkulu,Palembang, andLampung. |
| Java Time | Java tijd | UTC+07:30 | Java,Bali,Madura andKalimantan. |
| Celebes Time | Celebes tijd | UTC+08:00 | Sulawesi andLesser Sunda Islands. |
| Moluccan Time | Molukken tijd | UTC+08:30 | Ternate,Namlea,Ambon, andBanda. |
| New Guinea Time | Nieuw-Guinea tijd | UTC+09:00 | West Irian. Observed from1 November 1932 to 31 August 1944.[4] |
| Dutch New Guinea Time | Nederlandse Nieuw-Guinea tijd | UTC+09:30 | West Irian, then still namedDutch New Guinea was still controlled by theDutch. Observed from 1 September 1944 to 31 December 1963.[5] |
During theJapanese occupation of the Dutch East Indies, from 27 March 1942 to 24 September 1945, both western and central parts of Indonesia usedJapan 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 forDutch 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 EconomyHatta 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 usingUTC+08:00 may start on 28 October 2012.[8] However, in August, theJakarta 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 theIANA time zone database, Indonesia is given four zones in the filezone.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]
