Futabasaurus is a plesiosaur genus found in the Late Cretaceous rocks of Fukushima, Japan. It was officially identified and named in 2006 and classified within the family Elasmosauridae. The genus comprises a single species, F. suzukii.

Futabasaurus is believed to have measured approximately 6.4 to 9.2 meters (21 to 30 feet) in length and weighed around 700 kg (1,500 lb). It stands out from other elasmosaurids due to several distinguishing features, including a notable distance between the eye sockets and nostrils, fused interclavicles and clavicles with a bent anterior edge, a relatively long humerus, and slender femora with prominent muscle scars.

Futabasaurus presents a fascinating feature where its eyes and nostrils are notably distanced from each other. Paleontologists suggest this adaptation allowed the dinosaur to keep its nose above water while searching for food. By maintaining its nostrils exposed, it could continue to breathe as it hunted for prey.