Grateloupia asiatica is a red seaweed native to the coasts of Japan, Korea, and China. It has a branched thallus resembling a feather, dark reddish-brown in color, and 100–150 mm long. In North America, it is known from a single specimen collected from a dock in San Diego in 2012. Its likely vectors in San Diego are ballast water or hull fouling. It is established in the Thau Lagoon, in Mediterranean France, where it was probably introduced with Pacific Oysters.