Kaganaias (meaning 'Kaga water nymph') is an extinct genus of mosasauroid lizard that lived in what is now Japan during the Early Cretaceous. Kaganaias was semi-aquatic and is the only known aquatic squamate to be found in Asia and is also the only known aquatic squamate known from before the Cenomanian stage of the Cretaceous. It is also the first to be found in an inland area, instead of on the coast where aquatic squamates are commonly found.