The Antarctic Sound is a body of water about 30 nautical miles (56 km; 35 mi) long and from 7 to 12 nautical miles (13 to 22 km; 8 to 14 mi) wide, separating the Joinville Island group from the northeast end of the Antarctic Peninsula.

The northern limit of the sound, where it joins the Bransfield Strait, is the line connecting Cape Dubouzet (63°16'S, 57°03'W) on Trinity Peninsula with Turnbull Point (63°02'S, 56°36'W) on D'Urville Island.

Close to the north of Andersson Island lies the smaller Jonassen Island, the two being separated by the Yalour Strait which joins the Antarctic Sound to the Erebus and Terror Gulf part of the Weddell Sea.

[5][1] Another vessel trying to navigate the sound en route for Snow Hill Island in 1920, failed to get through and could not even reach Hope Bay, and "Operation Tabarin" in 1944 was beset by similar problems.

Birds that breed here include the gentoo penguin, brown skua, Antarctic tern, Wilson's storm petrel, kelp gull and snowy sheathbill.