Kelp forests are productive, biodiverse, marine ecosystems that occur throughout temperate and polar coastal zones. Those found growing on the rocky outcrops around Anticosti Island (Québec, Canada), which is situated in the Gulf of St. Lawrence, have been little studied. Underwater sampling was conducted in 2021 and 2022 to characterize the kelp community at 14 sites along the southwestern coast of the island. Five kelp species were recorded (Saccharina latissima, Alaria esculenta, Hedophyllum nigripes/Laminaria digitata, Agarum clathratum, and Saccorhiza dermatodea), in various assemblages among between sites. The density varied from 10 ± 5 to 99 ± 20 individuals·m−2 and the biomass, from 0.3 ± 0.1 to 6.4 ± 1.0 kg·m−2. These values are similar to those observed in other kelp forests in eastern Canada. Allometric relationships for S. latissima showed differences between certain sites, likely due to local environmental conditions. This characterization of the kelp forests along the southwestern coast of Anticosti Island highlights the ecological and economic potential of this ecosystem.