| Jacob Carstensen | |
| Fullname: | Jacob Frilund Carstensen |
| Strokes: | Freestyle |
| Club: | Sædding-Guldager, Esbjerg |
| Birth Date: | 10 September 1978 |
| Birth Place: | Kastrup, Tårnby |
| Height: | 1.930NaN0 |
| Weight: | 85kg (187lb) |
Jacob Carstensen (born 10 September 1978 in Kastrup, Tårnby) is a former freestyle swimmer from Denmark, who competed in three consequentive Summer Olympics for his native country, starting in 1996. He won the world title in the 400m Freestyle at the 1997 FINA Short Course World Championships (25m) in Gothenburg.