In the 1989 Southeast Asian Games in Kuala Lumpur, Malaysia, Buhain broke one of the existing SEA Games swimming records. In the 1991 Southeast Asian Games, where the Philippines was the host, he made a huge contribution to the gold medal record of the host country by winning most of the events in swimming. He was chosen to represent the Philippines in the 1992 Summer Olympics. He didn't win any medals in that sporting event.