Chronology of ASEAN Metrication:

Association of Southeast Asian Nations (ASEAN)

26 PHL Philippines

PHL Time Zone +8 Pilipinas (Philippines) Maynilà (Manila)
Metric System Introduced by Mother Spain: 1849
Metric System Adoption: 1906
Compulsory Metric Legislation: 1909
Compulsory Metric Implementation: 1973-75
United Nations Member: 24 Oct 1945
Note: International paper size A4 is the established ISO standard adopted by all countries in the world (except the United States and Canada) as well as the official United Nations document format size. Mexico, Costa Rica, Colombia, Venezuela, Chile and the Philippines are places where the US Letter Format is still in common use, despite their official adoption of the ISO standard.

41 THA Thailand

THA Time Zone +7 Prathet Thai (Thailand; formerly known as Siam) Krung Thep (Bangkok)
Compulsory for Public Works: 1889 *
Compulsory for Railways: 1892
Metric System Adoption: 1923
Compulsory Metric Implementation: 1936
United Nations Member: 16 Dec 1946
* Metric versus English [Published in 1921] Page 33

38 VNM Viet Nam

VNM Time Zone +7 Việt Nam (Vietnam) Hà Nội (Hanoi)
Metric System Adoption: 1911
Compulsory Metric Implementation: 1950
United Nations Member: 20 Sep 1977

40 KHM Cambodia

KHM Time Zone +7 Kampuchea (Cambodia) Phnom Penh
Metric System Legal Adoption: 1914
Compulsory Metric Implementation: 1922
United Nations Member: 14 Dec 1955

42 MMR Myanmar

MMR Time Zone +6.5 Myanmar – Myăma Nainngandaw (Burma) Yangon / Nay Pyi Taw (Administrative Capital)
Metric System Legal: 1920
International System Adoption: Incomplete
Compulsory Metric Implementation: Pending *
* Myanmar is preparing to adopt the International System (SI) as their official system of measurement, according to the Ministry of Commerce.
United Nations Member: 19 Apr 1948

34 IDN Indonesia

IDN Time Zone +7, +8, +9 Indonesia Jakarta
Metric System Adoption: 1923
Compulsory Metric Legislation: 1938
United Nations Member: 28 Sep 1950

39 LAO Pathet Lao

LAO Time Zone +7 Pathet Lao (Laos) Viang chan
International System Adoption: 1963
United Nations Member: 14 Dec 1955

29 SGP Singapore

SGP Time Zone +8 Singapura (Singapore) (city-state)
International System Adoption: 1968-70
Compulsory Metric Implementation: 1971
United Nations Member: 21 Sep 1965

28 MYS Malaysia

MYS Time Zone +8 Malaysia Kuala Lumpur
International System Adoption: 1971-72
United Nations Member: 17 Sep 1957

27 BRN Brunei Darussalam

BRN Time Zone +8 Brunei Bandar Seri Begawan
International System Adoption: 1985
Compulsory Metric Implementation: 1986-91
United Nations Member: 21 Sep 1984

Click on the image of Earth here to see when metrication occurred in each country or territory on Earth: