[1] He is a two-time silver medalist in the 1500 m freestyle at the Southeast Asian Games (2003 and 2005).

[2] Saengsri qualified for two events, as Thailand's youngest swimmer (aged 17), at the 2004 Summer Olympics in Athens, by posting FINA B-standard entry times of 3:59.91 (400 m freestyle) and 15:56.22 (1500 m freestyle) from the 2003 Southeast Asian Games in Hanoi, Vietnam.

He established a personal best and a Thai record of 3:59.89 to take a fourth spot in heat two, just 0.02 of a second faster than his entry time.

[5][6] In the 1500 m freestyle, Saengsri edged out Chile's Giancarlo Zolezzi and Malaysia's Saw Yi Khy to lead the first heat by a 6.06-second margin, breaking his own record time of 15:54.46.

Saengsri failed to advance into the final, as he placed twenty-seventh overall in the preliminaries.