Speed/distance meters were deployed on adeliée, gentoo and chinstrap penguins Pygoscelis adeliae, P. papua and P. antarctica, breeding near Anvers Island, Antarctica. Underwater speeds and distances travelled were interspecifically very similar (means of ca. 7–8 km h-1 and 15–45 km, respectively). These results are compared with published data on penguin behaviour at sea obtained by using identical methodology. A simple model, based on penguin activity at sea data, is developed to derive range limits for penguins. Derived range limits are substantially lower than previous estimates but accord well with distributional data obtained by transects.