Swimming at the 1959 SEAP Games was held in Bangkok, Thailand. The competition featured 7 male events swum in a long course (50m) pool.
| 100 m freestyle | Tin Maung Ni | 1:00.2 GR | Mya Thee | Tan Cheow Choon | 1:00.9 | ||
| 200 m freestyle | Tin Maung Ni | 2:17.7 GR | Mya Thee | 2:22.4 | Tan Cheow Choon | 2:24.8 | |
| 100 m backstroke | Lim Heng Chek | 1:11.5 GR | Tat Thang | 1:15.1 | Tan Gek Kee | 1:15.5 | |
| 100 m breaststroke | Truong Ke Nhon | 1:20.6 GR | Seah Pong Pin | 1:21.0 | Koay Thian Soon | ||
| 100 m butterfly | Lim Heng Chek | 1:13.5 GR | Seah Pong Pin | 1:13.7 | Phan Huu Dong | ||
| 4×100 m freestyle relay | 4:14.4 GR | 4:18.1 | 4:40.9 | ||||
| 4×100 m medley relay | 4:55.4 GR | ||||||