He posted FINA B-standards of 58.48 (100m backstroke) and 2:03.11 (200m butterfly) from the Southeast Asian Games in Bandar Seri Begawan, Brunei.

Swimming in heat two, he raced to third place in a matching entry time of 58.48, just a 1.36-second deficit behind winner Sung Min of South Korea.

[7][8] The following day, in the 200m butterfly, Phuangthong challenged seven other swimmers in the same heat, including 19-year-olds Zoran Lazarovski of Macedonia and Juan Pablo Valdivieso of Peru.

[9][10] At the 2001 Southeast Asian Games in Kuala Lumpur, Malaysia, Phuangthong collected a total of three medals: a gold in the 200m individual medley (2:05.75), and two silvers in the 100m backstroke (57.71), and as a member of the Thailand team, in the 4×200m freestyle relay (7:39.46).

[11][12][13] At the 2002 Asian Games in Busan, South Korea, Phuangthong finished seventh in the 100m backstroke at 59.04, holding off Singapore's Gerald Koh by 0.37 seconds.