Lago Frías is a glacial lake located within Nahuel Huapi National Park in the province of Río Negro, Argentina, in the Bariloche department, at approximately 41° South latitude. The lake has an elongated oval shape oriented north to south, with steep rock walls on both its eastern and western banks that are partially covered by vegetation and plunge directly into the water, giving the lake the visual character of a fjord. Its most striking feature is its emerald green color, produced by fine mineral particles carried by glacial meltwater originating from Cerro Tronador, the glacier-capped peak that forms the natural border between Argentina and Chile.

The surrounding landscape is dominated by the Selva Valdiviana, a temperate rainforest ecosystem found only in this corner of Argentina. The area receives approximately 3,500 mm of annual precipitation, with winter recording the highest rainfall. The humid winds blowing year-round from the Pacific Ocean sustain this dense, jungle-like vegetation. Paddlers should be prepared for wet and cold conditions in any season; waterproof gear, warm layers, and waterproof pants are strongly recommended. Summer mornings are generally considered the best time to experience the lake's emerald hues.

Access to Lago Frías is not straightforward. The primary route involves sailing across Lago Nahuel Huapi to Puerto Blest, approximately 25 km from Puerto Pañuelo near San Carlos de Bariloche. An alternative approach comes from the Chilean side via the Paso Pérez Rosales border crossing. There is no road access; all logistics depend on boat transport, and tickets and excursions should be booked well in advance. Puerto Blest serves as the main staging area, and guided kayaking trips depart from there. One route involves trekking through the Frías Valley along the Río Frías — whose turquoise and brown glacial-milk coloring contrasts with the lake's green — before reaching the lake itself.

The only habitable facility in the immediate area is the Puerto Blest Hotel, which sits within the Selva Valdiviana surrounded by Cerro Tronador and Cerro Tres Hermanos. The remoteness of the location means paddlers should plan self-sufficiency carefully, as services are extremely limited beyond what the hotel provides.