Laguna de los Tres is probably the most famous and most popular viewpoint for Cerro Fitz Roy. "Los Tres" refers to the three peaks that you can see from the laguna's shore: Fitz Roy (3,405m), Poincenot (3,002m), and Saint-Exupéry (2,558m), but the view is magnificient around all 360 degrees.

This is a very popular destination, for good reason, so don't expect any solitude if you're there between November and February. The path up is well trodden and relatively easy going, with some steeper sections towards the top.

Whilst there's only one approach to the laguna and the viewpoint, you can incorporate it into your itinerary in a few different ways:

 - Day hike from El Chalten. This is a route where you have to retrace your steps, but it's a varied and interesting route and the round-trip might take around 8 to 9 hours.
 - Start from Hosteria Pilar or Piedra del Fraile campsite to the North, and return back to El Chalten at the end of the day. This is again a full day of around 8 to 9 hours, but has the benefit of taking in Glaciar Piedras Blancas in the first part of the day, and you don't need to retrace your steps.
 - Use Camping Poincenot as base. This is a good option if you want to break it into shorter days; from here it's about an hour up to the viewpoint. The campsite is nice, if a little busy, and around a 3 hour hike from El Chalten.