This dataset describes the occurrences of 19 species of macroalgae along standardized transects in the Bay of Calvi (Corsica). This dataset was based on 2 different campaigns (one in 2016 and one in 2019) in the Bay of Calvi. In both campaigns, an underwater remotely operated vehicle (ROV) was deployed in the Bay and navigated along straight transects perpendicular to the coastline. The ROV was equipped with a down-looking GoPro camera, to capture footage of the bottom, and a built-in front-looking camera to capture a general view of the landscape and navigation. Algae were identified and their coverage was quantified using the down-looking videos. The species of macroalgae are the following : Acetabularia acetabulum, Amphiroa rigida, Caulerpa prolifera, Caulerpa cylindracea, Codium bursa, Colpomenia sinuosa, Corralinales (order), Cystoseira brachycarpa, Cystoseira crinita, Cystoseira spinosa, Cystoseira zosteroides, Dictyota (genus), Flabellia petiolata, Halopteris (genus), Halopteris scoparia, Jania (genus), Osmundaria volubilis, Padina pavonica, Peyssonnelia squamaria. In this project, each of the "events" represent different transects navigated by the ROV. The points on the map are the location of the beginning of each transect (located on the coast). From this point, the ROV navigated perpendicularly to the coast until the end of the rocky shore. The actual geographic position of each algae is not recorded, but only the presence of each algae species along this transect.