During a biodiversity expedition to the northern cays of the Archipelago of San Andrés, Old Providence and Saint Catalina, we collected macroalgal samples along Quitasueño Bank, a submerged 60 km-long coralline bank. This is the fist phycological study on the bank. We present a preliminary list of 76 macroalgae, including ten species of cyanobacteria. Fifteen of these taxa are new records for Colombia, and an additional nine are new records for the Archipelago. With this preliminary study, we increase the number of taxa in the macroalgal flra of this region of Colombia by 10.1%.