AbstractThe macroalgal flora of Cantabria (north of Spain) has attracted the interest of many researchers on past occasions. Currently published information only reflects occasional collections from sporadic field visits to this region of the Spanish Atlantic coast. To overcome this, a historical overview of research and publications, encompassing collections and presence data recording, has been undertaken. This work lists the resultant taxonomic records and provides information about macroalgal flora of Cantabria. A total of 425 species (25 Cyanobacteria, 55 Chlorophyta, 81 Ochrophyta, and 264 Rhodophyta) were identified. The number of specific, infraspecific taxa, and stages is 437: 25 Cyanobacteria, 57 Chlorophyta, 89 Ochrophyta, and 266 Rhodophyta. The floristic character of flora from the Cantabrian coast is compared over time and with nearby regions applying Cheney’s ratio [(Rhodophyta+Chlorophyta)/ Ochrophyta, or (R+C)/O]. The present paper aims to provide an overview of the research that has been conducted in the Cantabrian coast, not only found in international publications but also in local publications as well as unpublished theses.