An ethogram is provided for the small, intertidal, diurnal octopus Abdopus aculeatus (d'Orbigny, 1834). Information is based primarily on in situ observations of adults, and supplemented with photographs of animals in aquaria. Aspects of the dymantic display, mating system, activity patterns, and habitat use appear similar to those expressed by other members of Abdopus, as well as the large sister taxon Octopus cyanea, suggesting that these behaviours may be conserved throughout the evolution of these octopuses. Many skin components are also shared with Octopus bimaculoides, which may reflect either an evolutionary affinity with this octopus, or convergence in these characters. If behavioural units such as those documented here are compiled in a consistent manner for other species, then they may facilitate taxonomic identification, as well as future evolutionary studies of octopodids.