This chapter explores the underwater seascapes of Isla de los Estados, where both kelp forests and animal forests flourish. These underwater ecosystems are shaped by organisms that act as ecosystem engineers, enhancing habitat complexity and supporting high biodiversity. Kelp forests are primarily formed by brown macroalgae of the order Laminariales, while animal forests by dense aggregations of habitat-forming invertebrates. Even though animal forests also play a crucial role in ecosystem structure, they remain less studied, with significant knowledge gaps regarding their distribution and functioning. Based on a scientific diving expedition conducted in 2022, we described the underwater forests of Isla de los Estados using photo-quadrats and the Roving Diver Method. We identified over 230 taxa of mobile and sessile invertebrates, macroalgae, and fishes, revealing highly diverse communities and documenting new records of algae and invertebrates. A photographic catalog of the observed taxa was compiled, resulting in the upload of more than 1800 underwater images to the open-access platform iNaturalist. This study underscores the exceptional conservation status and ecological richness of Isla de los Estados’ underwater forests. Potential threats are discussed, such as the presence of the invasive anemone Metridium senile, along with proposed strategies for monitoring and conservation.