Ushuaia's bookable activities are mostly on the Beagle Channel: catamarans out past the Les Éclaireurs lighthouse and the sea-lion islands, and the trip east to Isla Martillo, the only penguin colony in Tierra del Fuego, where Magellanic and a few gentoo penguins breed between October and April. The municipality publishes an official list of the operators running the penguin-colony trips, and two of the operators below are on it.
Away from the water, the operators below guide the Laguna Esmeralda and glacier treks, drive 4x4s out to Lago Escondido and Fagnano and along the Ruta de la Centolla, paddle the Lasifashaj river, run birding walks and fat-bike trips across the winter ice, and sell berths on the Antarctic expedition ships that leave from the port. Most of them appear on the tourism secretariat's register of agencies, which lists the address and contacts each one supplies.