ASEAN Common Time
The ASEAN Common Time (ACT) is a proposal to adopt a standard time for all Association of Southeast Asian Nations member states. It was proposed in 1995 by Singapore, and in 2004 and 2015 by Malaysia to make business across countries easier. The proposal failed because of opposition in Thailand and Cambodia.
Currently, there are four different time zones used by ASEAN countries, such as UTC+06:30 (Myanmar); UTC+07:00 (Cambodia, Laos, Thailand, Vietnam, and western Indonesia); UTC+08:00 (Singapore, Malaysia, Brunei, Philippines, and central Indonesia); and UTC+09:00 (eastern Indonesia).
The proposal would institute UTC+08:00 as the ASEAN Central Time, putting Myanmar at UTC+07:00, and leaving the less populous eastern Indonesia at UTC+09:00. This would result in the vast majority of the region's people and territory lining up at UTC+08:00—in sync with China, Hong Kong, Macau, Taiwan, and Western Australia, while eastern islands of Indonesia would remain at UTC+09:00—in sync with Japan, South Korea, North Korea, East Timor and Palau.
Some regional businesses have already begun adopting the phrase "ASEAN Common Time", also using the abbreviation ACT, in their press releases, communications, and legal documents. The idea has since been under discussion by ASEAN, with Singapore supporting it strongly. 
|ASEAN relation||Country||UTC offset||Time Zone
|ASEAN members||Myanmar||+06:30||MMT||Some experts suggest that moving to UTC+07:00, rather than UTC+08:00, would be a more natural change.||Myanmar Standard Time|
|Thailand||+07:00||ICT||Tried unsuccessfully to switch to UTC+08:00 in 2001 by then-Prime Minister Thaksin Shinawatra. Issue remains under discussion.||Time in Thailand|
|Laos||Time in Laos|
|Vietnam||From 13 June 1975 after reunification||Time in Vietnam|
|Cambodia||Time in Cambodia|
|Indonesia||+07:00||WIB||A single national time zone of UTC+08:00 has been proposed, however it is unclear when or if it may be implemented. ||Time in Indonesia|
|Singapore||+08:00||SST/SGT||From 1 January 1982, except for Japanese occupation of Singapore during World War II.||Singapore Standard Time|
|Malaysia||MYT/MST||Peninsular Malaysia switched from UTC+07:30 on 1 January 1982, and East Malaysia uses it since 1933, except for the Japanese Occupation during World War II.||Time in Malaysia|
|Brunei||BNT/BDT||Time in Brunei|
|Philippines||PHT/PST||First implemented on 31 December 1844, and became permanent on 29 July 1990 when the country ended the use of daylight saving time, then set at UTC+09:00.||Philippine Standard Time|
|ASEAN observer states||Timor-Leste||+09:00||TLT||Time in Timor-Leste|
|Papua New Guinea||+10:00||PGT||Time in Papua New Guinea|
|ASEAN Plus Three||Japan||+09:00||JST||Japan Standard Time|
|South Korea||KST||Time in South Korea|
|People's Republic of China||+08:00||CST||Time in China|
- "Press Statement The First Informal ASEAN Heads of Government Meeting Jakarta". 30 November 1996. Archived from the original (Press release) on 14 February 2006.
- "Joint Communique of The 29th ASEAN Ministerial Meeting (AMM) Jakarta, 20-21 July 1996". Archived from the original on 8 January 2006.
- Abdullah Ahmad Badawi (7 August 2004). "Towards an ASEAN Community". Archived from the original (speech) on 17 October 2004.
- Time in Southeast Asia
- "Association of Southeast Asian Nations · ASEAN Anthem". Aseansec.org. Archived from the original on 1 June 2013. Retrieved 12 October 2013.
- "The Nation - Google News Archive Search". news.google.com. Retrieved 25 February 2019.
- Com, The Phuket News (25 April 2015). "Thailand News: Asean unlikely to agree on common time zone". The Phuket News Com. Retrieved 18 August 2020.
- Media, Kompas Cyber. "Pengaruh Letak Astronomis ASEAN". KOMPAS.com (in Indonesian). Retrieved 18 August 2020.
- Sunday, 26 Apr 2015 11:11 PM MYT. "Proposal for common Asean time zone put on hold, Anifah says | Malay Mail". www.malaymail.com. Retrieved 18 August 2020.
- "Remarks By Foreign Minister George Yeo In Parliament In Response To Question On Asean Cooperation". mfa.gov.sg. 2 September 2004. Archived from the original on 14 July 2012.
- "A common Asean time zone? 6 things about time differences in the region". The Straits Times. 30 January 2015. Archived from the original on 2 August 2019. Retrieved 21 June 2019.
- "Time Zone Abbreviations – Worldwide List". timeanddate.com.
- "Hatta : Penyatuan Zona Waktu Tidak Batal". economy.okezone.com (in Indonesian). 9 February 2013. Archived from the original on 4 March 2016. Retrieved 2 February 2017.
- Schedler, Joseph (1878). An illustrated manual for the use of the terrestrial and celestial globes. New York. p. 27.
- "Time Zone & Clock Changes in Manila, Philippines". www.timeanddate.com.