The aim of this work was to carry out a qualitative assessment of the subtidal algal assemblages occurring at Fildes and Collins Bays. We conducted subtidal sampling of seaweeds between 1 and 10 m in Collins and Fildes Bay during late summer 2009. Our results showed that Rhodophyta was the most diverse group (63% of species) followed by Phaeophyceae (33.3%) and Chlorophyta (3.7%). Differences in species richness and structure of algal assemblages were recorded between sites. Depth significantly influenced algal assemblages; however there was a significant interaction between site and depth, suggesting that the effect of depth varied among sites. Observed differences between sites may be explained by differences in ice-scour disturbance, habitat heterogeneity (availability of refugia) and identity of canopy-forming species.