Sickle seagrass is a flowering plant that is found in subtropics oceans and can grow up to be 30 cm in length. They are found in shallow sandy areas about a few meters deep. They dig their stems about 10 cm into the sand and stretch them sideways. Thin leaves come out from the joints of these stems. From autumn to winter, small white flowers bloom.

Sickle seagrass and other underwater flowering plants are classified as seagrass, while plants like brown seaweed (wakame) and kelp are called seaweed.

Sickle seagrass is the most popular seagrass in Okinawa. They become food for sea turtles and dugongs as well.