Nuphar × saijoensis is a species of rhizomatous aquatic plant endemic to Japan.

[1] The type specimen was collected by Michiko Shimoda in Higashi-hiroshima City, Hiroshima Prefecture, Japan on the 27th of June 1989.

[7] Different sources list different species involved, depending on the recognition of Nuphar taxa.

Nuphar japonica is listed as a parental species in all sources.

[4][5] It only occurs in aquatic habitats, such as irrigation ponds, of the Saijo Basin, western Japan.