Taun Ushuaia is a local tour operator specializing in adventure and outdoors tourism.
I went on their packrafting excursion on Rio Olivia. It was spectacular, challenging but just enough to make it exciting with no suffering. We wore our packrafts for a 40 minute hike to Laguna Mariposa, where we inflated the rafts. After an instructional briefing we hit the water, paddling down the undulating Olivia River. I highly recommend the experience - you can book here.

Check their official site for other tours - like guided hikes for challenging trails like Ojo del Albino Glacier and Vinciguerra Glacier.