Kaganaias (meaning 'Kaga water nymph') is an extinct genus of basal and oldest dolichosaur[2][3][4][5] that lived in what is now Japan during the Early Cretaceous.

[6] Its generic name is derived from Kaga Province, the old name for the Ishikawa Prefecture where the specimens were found, while the species name hakusanensis comes from the mountain that gives its name to Hakusan the city near its find site.

[6] Kaganaias lived in what was a fertile, inland swamp-like region of Japan, possibly a large floodplain which was covered with water for most of the year.

Kaganaias almost certainly moved through the water using a snake-like swimming motion, using its short hind legs to navigate.

Kaganaias probably fed on other small vertebrates or molluscs which have been found in the surrounding area, but this has yet to be confirmed by the results of the examination of the fossil's faecal remains.