During January/February 2006, we satellite-tracked two different ecotypes of killer whales (Orcinus orca) in McMurdo Sound, Ross Sea, Antarctica, using surface-mounted tags attached with sub-dermal darts. A single Type B whale (pinniped prey specialist), tracked for 27 days, traveled an average net distance of 56.8 ± 32.8 km day⁻¹, a maximum of 114 km day⁻¹, and covered an estimated area of 49,351 km². It spent several days near two large emperor penguin (Aptenodytes forsteri) colonies, a potential prey item for this form. By contrast, four Type C killer whales (fish prey specialists) tracked for 7–65 days, traveled an average net distance of 20 ± 8.3 km day⁻¹, a maximum of 56 net km day⁻¹, and covered an estimated area of only 5,223 km². These movement patterns are consistent with those of killer whale ecotypes in the eastern North Pacific where mammal-eating ‘transients’ travel widely and are less predictable in their movements, and fish-eating ‘residents’ have a more localized distribution and more predictable occurrence, at least during the summer months.