A crustose red alga, Lithophyllum neo-okamurae A.Kato, D.Basso, Caragnano, Rodondi, V.Peña & M.Baba, is reported a new record from Korea and its biogeographic distributions are extended in Korea. Lithophyllum neo-okamurae has been known as endemic species in Japan. Despite the resemblance between L. neookamurae and L. okamurae, our molecular and morphological analyses have revealed the simultaneous presence of both species in Korea. Although L. neo-okamurae and L. okamurae share morphological similarities, there are notable variations in gene sequences, with a range of 9.1-11.3% in psbA and 14.8-15.3% in rbcL. Specifically, while L. neo-okamurae is distributed throughout the entire coastline of Korea, L. okamurae is predominantly found in southern region. Furthermore, our analyses have revealed their detailed distributions in Korea.