A Natales family business that has been running boats up the Última Esperanza fiord since 1965, which makes them older than the tourism industry they now serve. The flagship trip crosses the fiord to the Balmaceda and Serrano glaciers in the Parque Nacional Bernardo O'Higgins, past cormorant colonies and hauled-out sea lions, and it is the standard way to see that park without a private boat.
They also run the back door into Torres del Paine: sail to Hostería Monte Balmaceda, walk or ride up the Serrano, and enter the park from the south instead of the bus road. Add trekking on the Camino del Fiordo, e-bikes and horses at their Estancia Perales, and four vessels of their own.
The office is on Eberhard, open 08:00 to 20:00 daily in high season and 09:00 to 19:00 out of it. They publish no prices on the website — the price field on the main excursion page still reads "Desde $XX.XXX". Ask by WhatsApp; the number is printed in full beside the link.