Torres del Paine O Circuit

The O Circuit is the full circumnavigation of the Cordillera del Paine — 130 km over 8 to 10 days, looping around the back of the massif and then completing the W along its front. It includes everything the W shows you plus the remote back side: the windswept Serón and Dickson valleys, the moraines below Glacier Los Perros, and the dramatic east-to-west crossing of John Gardner Pass at 1,200 m with the Southern Patagonian Ice Field unfolding below as you crest the saddle.

CONAF, the park service, enforces counterclockwise travel — every hiker crosses John Gardner east-to-west, both for safety on the steep west side and to keep traffic moving in one direction along the narrow back-country sections. Day 1 starts at Hotel Las Torres and walks gently north up the Río Paine valley to Campamento Serón. Day 2 climbs to Lake Paine and continues to Dickson, on the lake of the same name with the Dickson Glacier filling the head of the valley. Day 3 is a short walk through forest to Los Perros, the last camp before the pass. Day 4 is the crux: a pre-dawn start, 900 m climb to John Gardner Pass on rocky moraine, then a 1,300 m descent on chains and ladders past the calving Grey Glacier to Refugio Grey. Day 5 onward picks up the W along the south shore of the Paine massif — Paine Grande, French Valley, Los Cuernos, and the final pre-dawn climb to Mirador Las Torres on day 8.

The O is open November to March only (a tighter window than the W) — outside it, the back side is closed and unsafe. Bookings are mandatory for every night and the back-side camps (Serón, Dickson, Perros) fill earliest because there are no alternatives if you miss one. Wild camping is prohibited park-wide. Most hikers go with a tour operator to handle the logistics of multi-concession bookings, food drops, and Spanish-language coordination, but independent travel is entirely possible — book each refugio individually on Vértice's and Las Torres's websites the moment reservations open in June. The crux remains weather: Patagonia's wind and rain on the pass day can turn the route from spectacular to genuinely dangerous in an hour.