Limnobiophyllum expansum (Lemnoideae, Araceae) was newly found in the lower Miocene (18.4–17.0 Ma) Hiramaki Formation of the Mizunami Group in the Kani Basin, Gifu Prefecture, central Japan. This genus was distributed widely in the Northern Hemisphere from the Late Cretaceous to the Paleocene, but a Miocene descendant (L. expansum) was reported only from Europe, in the Bohemian Basin, Czech Republic (early Miocene), Paldau, Austria (late Miocene), Schrotzburg, Switzerland (late Miocene) and Sośnica, Poland (late Miocene). Our finding is the first record of a Miocene Limnobiophyllum from an area other than Europe. The aquatic flora of Japan during the early Miocene is poorly documented, but this finding suggests a link between the aquatic floras of Europe and Asia.