Acrophoca longirostris, also known as the swan-necked seal, is an extinct genus of Late Miocene pinniped.

[2][3] Acrophoca was around 1.5 metres (5 ft) long, and was not as well adapted to swimming as its descendants, possessing less developed flippers and a less streamlined neck.

Unlike other earless seals, Acrophoca had a long and flexible neck, with an elongated body.

The orientation of the pelvis, which in comparison to modern earless seals is everted, as well as adaptations to the hind limbs suggest that swimming was mainly powered by the back flippers.

[3][4] Its fossils have been found alongside those of the marine sloth Thalassocnus and tusked cetacean Odobenocetops, as well as modern animals such as bottlenose dolphins, gannets and cormorants.