O Circuit Day 4 in Torres del Paine: from Los Perros Camp to Grey Sector

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The Toughest (and Probably Most Spectacular) Day of the O Circuit

After a good rest following Day 3’s hike, we begin the fourth stage of our trek: O Circuit – Day 4. Today’s route takes us from Los Perros Campground to the Grey Sector. Here are the key details:

Here’s what today’s hike looks like:

Distance: 10.6 miles (17 km)

Time in motion: 6h 20 min

Total time: 9h 20 min

Accumulated positive difference in altitude: 2,927 feet (892 m)

Accumulated negative elevation gain: 4,518 feet (1,377 m)

Difficulty: high

Route in Wikiloc

Improvised Breakfast and Mandatory Departure Before 7:00 AM

The day starts early. Los Perros doesn’t offer breakfast or lunchboxes, so we dig into the stash we packed in Puerto Natales—instant coffee, bread, nuts, granola bars, and leftover protein bars from previous lunchboxes. It’s enough to cover breakfast and lunch. Keep in mind that meal services at Los Perros change from year to year.

⚠️ Important: Staff at Los Perros will hurry you out if you haven’t left by 7:00 AM. It’s not arbitrary—it’s for your safety.

Climbing John Garner Pass: Mud, Forest, and… Glaciers!

It’s raining and we face a steady climb toward the famous John Garner Pass. The first part takes us through dense forest where the mosquitoes are still active. Mud, exposed roots, and technical sections slow our pace, but what matters most is getting through.

We emerge from the forest and reach the first viewpoint. Then it’s on to a new stretch, where the tall trees give way to low brush and finally to rocky terrain. A glacier appears on our right, and we keep getting closer.

The Descent: Technical, Long, and Otherworldly Views

The final stretch up John Garner Pass feels like scaling a staircase built for giants—huge rocks everywhere. It levels out, we cross a snowy patch, and within minutes a cloud from the valley rolls in. It starts to rain heavily. But then, we cross the pass and there it is: the mighty Grey Glacier. It’s immense. We watch as smaller glaciers from nearby valleys feed into it, like tributaries joining a river. It might just be the biggest WOW moment of the entire O Circuit.

We hear that the snowy stretch—just a few centimeters today—was 12 inches (30 cm) deep last week. That’s why gaiters are strongly recommended for this section of the trek.

The descent begins—steep and technical, and dangerous if rushed. Gradually, the skies clear and the glacier starts to glow under the sunlight. Wait… are those mosquitoes again? We continue down a bare trail, and suddenly—reward! A rainbow over the glacier.

The second section of the descent is a narrow trail with constant switchbacks, loose rock, and lots of exposed roots. It’s hard to find a rhythm. We adapt to the terrain and the descent feels endless. Legs start to burn, but we know we’ll stop for lunch at El Paso Campground. Every step brings us closer to the glacier, as we follow the path down the valley side. We finally reach a flatter area and begin to cross small streams. We’ve been walking for miles alongside a glacier—and that realization never stops feeling magical.

Arrival at El Paso Campground

We reach El Paso Campground, check in with CONAF staff, and chat with the rangers. They mention a new shelter is being built here to help shorten what’s considered the hardest day of the O Circuit in Torres del Paine. We have lunch in a shed with a couple from San Diego and San Francisco, share stories, and continue onward. We’ve still got exactly what the signpost shows ahead—and honestly, it might be the most accurate sign in the whole park.

Hanging Bridges, Grey Viewpoint, and Arrival at the Refugio

We keep descending slowly beside the glacier, now getting closer to the front, we pass Nunatak Island—a landmass that used to be entirely surrounded by glacier ice, but is now only partially encircled due to glacial retreat.

We cross three massive hanging bridges—definitely not for those with vertigo—and pass the Grey viewpoint. This is a popular stop for trekkers coming from Grey Refugio, especially those on the W Trek.

End of the Stage: Grey Sector and a Well-Deserved Beer 🍻

We finally arrive at Grey Refugio. First things first—we grab a beer and enjoy it on the terrace, laughing with the couple we met earlier at El Paso. The vibe is completely different now. We’ve left behind the park’s remotest zone and are entering the sections with larger refugios.

We wrap up a day with over 10.5 miles, nearly 3,000 feet of climbing, and more than 5,000 feet of descent on terrain that’s left our legs feeling like Playmobil figures.

End of Circuit O – day 4. More tomorrow, but I doubt if it will be better…

Tips for the Los Perros – Grey stage

✅ Bring breakfast and lunch prepared from previous stages.
✅ Leave no later than 7:00 AM.
✅ Gaiters: highly recommended if there is snow on the pass.
✅ Take it easy on the descent, especially if it has rained.
✅ Bring battery and room in your camera. You don’t want to miss the pictures of Grey Glacier.

Do you want to know how the adventure continues? 👇
➡️ Day 5: Grey Sector – Paine Grande