A true prize for pioneering adventurers, Antarctica’s tallest volcano and one of its most remote peaks awaits: Mount Sidley. Towering above the vast white expanse of Marie Byrd Land, this dormant giant offers a rare opportunity to explore untouched terrain where few have ever set foot. With its dramatic caldera, sweeping icefields, and sense of absolute isolation, Mount Sidley is more than a summit—it’s a bold step into the unknown, perfect for those seeking the ultimate off-the-map experience.

Antarctica's Highest Volcano

Be among the few to have climbed Antarctica’s highest volcano and one of the Volcanic Seven Summits. Join the ultimate mountaineering expedition to Mount Sidley 14,058ft (4285m) and stand atop one of the most remote summits on earth.

Sidley is a huge mountain, set on the white expanse of the Polar Ice Sheet. This majestic peak features

a 3mi (5km) wide caldera and sheer walled amphitheater, created by an explosive eruption 4.7 million years ago. Blue-ice slopes guard the upper mountain and fantastical snow mushrooms sprout along the upper ridge, leading to the summit.

Mount Sidley was first climbed in 1990 by New Zealander Bill Atkinson and saw its second ascent in January 2011 by an ALE-guided team. Our team established a new route up the east ridge and traversed all three summits. Plenty of lines remain to be climbed and ALE continues to lead the way in exploring this remote peak in Antarctica.

Itinerary

day -3-0 | Arrival Day Punta Arenas, Chile

Pre-departure Days
Flight Check-in &
Baggage Drop-off
Welcome & Safety Briefing

Known as the gateway to Antarctica, all of our flights depart from the Chilean city of Punta Arenas.

We ask you to arrive in Punta Arenas at least three nights prior to your trip start date. Here you will meet your fellow team members, pack expedition food rations, and complete the pre-departure process. The pre-departure period also provides a buffer for flight and luggage delays should your travels to Chile not go as planned. We do not hold Antarctic flights for delayed passengers or luggage.

We will be waiting for you in the terminal when you arrive at Punta Arenas airport and will transport you to your hotel. The following day, you will have an individual Gear Check at your hotel, where we will review the personal clothing and equipment you will need in Antarctica.

The day before your Antarctic flight there is a Welcome and Safety Briefing in the ALE Office. Here we will explain the flight dispatch process, review environmental and safety.

day 1 | Fly to Antarctica

At the Punta Arenas airport, you will check-in for your flight, pass through normal Airport Security then board our chartered jet for the 4 hour flight to Antarctica. Our route crosses the Drake Passage, then follows the west side of the Antarctic Peninsula and the spine of the Ellsworth Mountains. We land on a naturally occurring blue-ice runway on Union Glacier where you will take your first steps in Antarctica.

Climb aboard one of our specially-adapted vans for the 5 mi (8 km) shuttle to our main camp. Our friendly staff will provide a welcome tour of camp and show you to your tent.

day 2-3 | Expedition Preparations

You will meet your guide at Union Glacier Camp and begin expedition preparations with your team. Over

the next days, you will also climb some small peaks near camp to acclimatize to Antarctic conditions, get to know your team, and fine tune your clothing and equipment before setting off for Mount Sidley

day 4 | Fly to Mount Sidley

Mount Sidley is located in the Executive Committee Range, about 550mi (885km) from Union Glacier. When weather conditions permit, your team will fly by ski aircraft for about five hours over the vast emptiness of West Antarctica. Upon landing, you will set up base camp at approximately 6700ft (2042m), below the imposing bulk of the mountain.

day 5-10 | The Ascent

Mount Sidley has been climbed by just a handful of teams and there is still opportunity for exploring

new routes. The mountain offers several interesting options, including a longer, easy ascent from the

north side and a steeper climb up the west ridge from the Bennett Saddle. Your guide will assess the

options and decide on a route based on the group’s skill and experience.

From base camp to the summit of Mount Sidley involves approximately 7300ft (2225m) of elevation gain. You will climb alpine-style, setting intermediate camps on the mountain, and carrying all of your food and equipment with you. Although you may use skis lower down on the mountain, most of the climb will be done with crampons.

The slopes of the mountain are wind-blown, with hard packed snow and sections of blue-ice. Gentle slopes near the base give way to steeper terrain higher up.

Summit day offers spectacular views as you follow up the summit ridge along the rim of the caldera. The walls of the Weiss Amphitheater drop steeply away below you and neighboring Mount Waesche may tempt you with its snowy slopes.

As you make your way to the summit ridge, you’ll weave your way between a fantastical maze of snow mushrooms. These massive snow features are formed by wind and moisture depositing rime ice on small obstacles over time.

Following the summit, you’ll return to your high camp, then retrace your steps back to base camp.

day 11 | Return to Union Glacier

Our field staff will stay in close contact with Union Glacier Camp to identify the best ‘weather window’ for your return flight.

Depending on flights, you may have at least one day at the end of your experience to explore more of Union Glacier. You will also enjoy a celebration event and receive a certificate to commemorate your Mount Sidley Expedition.

day 12 | Return to Chile

When weather and runway conditions permit, our intercontinental, passenger aircraft will arrive at Union Glacier to transport you back to Chile. Our staff will meet you at the airport and transfer you to your hotel.

Fly Home

Your flight home concludes this remarkable adventure. We recommend keeping a flexible schedule due to the possibility of weather delays. Allow yourself to savor your experience without the pressure of other commitments.

Ships

Union Glacier Camp

This is a land tour destination in Antarctica

Crafted for the extremes, our Antarctic camps are a testament to precision engineering and logistical mastery. Whether you’re staying at Union Glacier Camp nestled by Mount Rossman, or traveling to one of our remote camps, each site is primarily powered by renewable energy systems and supported by expert field staff trained in polar operations. Refined with our nearly half a century of experience in the interior of Antarctica, our camps are optimized for safety, sustainability, and a once-in-a-lifetime immersive experience.

Union Glacier Camp is the only full-service private camp of its kind on the continent. More than just a place to stay, Union Glacier is the central hub of Antarctic exploration. It offers comfortable accommodations for guests on guided adventures while also serving as a vital logistics center—supporting private expeditions, scientific research teams, and National Antarctic Programs from around the world.

What's included