| Brunei Darussalam |
December 15, 1987 |
Ratification : June 28, 1988 |
August 2, 1988 |
|
| Indonesia |
December 15, 1987 |
Ratification : April 30, 1999 |
May 29, 1999 |
|
| Lao People's Democratic Republic |
December 15, 1987 |
Ratification : July 25, 1988 |
August 2, 1988 |
|
| Malaysia |
December 15, 1987 |
Ratification : July 23, 1997 |
August 21, 1997 |
|
| Philippines |
December 15, 1987 |
Ratification : January 27, 1988 |
August 2, 1988 |
|
| Singapore |
December 15, 1987 |
Ratification : January 24, 1989 |
February 22, 1989 |
|
| Thailand |
December 15, 1987 |
Ratification : June 17, 1988 |
August 2, 1988 |
|
| Viet Nam |
|
Accession : August 16, 1996 |
September 14, 1996 |
|