Nine Adelie Penguins (Pygoscelis adeliae), 4 females and 5 males, were tracked by radio telemetry when they went to sea from the Northern Rookery, Cape Bird, Antarctica, on their first foraging trips of the incubation period. Each penguin took a different direction on leaving the rookery but maintained its approximate heading, suggesting that it was navigating. Radio contact was lost after 2-12 days as birds moved beyond the 100 km radio horizon. The penguins spent about one-third of their time on ice floes. Most of their time in the water was spent diving and feeding. Dives (including underwater swimming) lasted for a mean of 92.5 s , followed by a mean recovery period of 33.8 s. The length of the recovery period was significantly correlated with the length of the dive. From the maximum dive times, the duration of “feeding” dives, and the dive: pause ratios, Adelie Penguins seem to have diving abilities between those of the other two pygoscelid penguins, the Gentoo and Chinstrap. We hypothesize that the Adelie Penguins may travel large distances from the rookery during the incubation period so as to forage on the larger and more pelagic krill, Euphausia superba.