Ceramium sungminbooi is a filamentous red alga described by J.R.Hughey & G.H.Boo in 2016. It was originally identified as C. cimbricun, described from Denmark in 1924. However, recent specimens from California (San Francisco Bay), Oregon (Yaquina and Coos Bays, Denmark (Limfjord) and Norway (Oslofjord) grouped genetically with specimens from Korea.. The thalli are pink to rose red, and finely branched. The apices (tips) of the branches are double and slightly incurved. the branches are marked by. regular bands of dark-red cortical cells . The plants are bush or-fan-shaped, and grow to 30-80 mm tall. The plants in San Francisco Bay were growing in marinas, near yachts, while European specimens were growing in area near shellfish farms. In both regions. C. sungminbooi was found in association with other nonndigenous algae from the Northwest Pacifc. Possible vectors include hull fouling, ballast water and oysters. Although it had not been previously reported from Japan, it was found on debris from the 2012 Great East Japan Tsunami, on the coasts of Oregon and Washington. Impacts have not been reported for this alga on the Pacific coast..