Puerto Williams is a city, port, and Chilean naval base situated on Navarino Island, facing the Beagle Channel.

It serves as the capital of Antártica Chilena Province within the Magallanes and Chilean Antarctica Region, and is widely recognized as the world's southernmost city, with a population of roughly 2,874.

The area has been inhabited for more than 10,000 years, originally by the Yaghan people, whose last descendants live today in Villa Ukika, a small community just outside town. The city has no land access.

Connections include a weekly 32-hour ferry from Punta Arenas and, during high season, a roughly two-hour boat crossing of the Beagle Channel from Ushuaia, Argentina, weather permitting. Daily flights on small aircraft also link Puerto Williams to Punta Arenas.

The town serves as a gateway to Cabo de Hornos National Park and Alberto de Agostini National Park, and is a recognized meeting point for adventurers and scientists exploring the far southern reaches of Patagonia.