Cerro San Lorenzo

Climb Patagonia With Alpine Ascents

I very much enjoyed the expedition. The overall quality was excellent, particularly given that this was AAI’s first expedition to Cerro San Lorenzo. Everything from lodging to group gear to food to the itinerary were well planned and executed and the guides were adept at making changes as circumstances dictated. The experience was both fun and challenging.

First climbed by 60-year-old climber Padre Alberto Maria de Agostini, Cerro San Lorenzo is a demanding peak with just rewards. At 3,706 m (12,159 ft.) this is the second highest peak in the Patagonian Andes. It has heavily glaciated terrain in an extremely remote location. Rising out of the Patagonian Pampa (plains), east of the Campo de Hielo Norte (Northern Patagonian Ice Field), Cerro San Lorenzo is blessed by a relatively sunny micro-climate and generally experiences better weather than much of wind-whipped, rainy Chilean Patagonia. With more balanced weather throughout the region, Cerro San Lorenzo is one of the few accessible peaks, adding to the allure.

Alpine Ascents’ expedition to Cerro San Lorenzo provides an excellent opportunity for fit and intermediate climbers (i.e., climbers who have had a strong performance on our 6-day mountaineering course or better) to apply the skills learned in our courses or on other glaciated peaks, in an international setting. Along the way, expedition members will experience the unique culture of Chilean Patagonia – with travel along the Carretera Austral (Southern Patagonian Highway). Expedition members will interact with horse packers and spend time around a campfire partaking of a traditional Chilean asado (barbeque).

For climbers intending to climb Denali with Alpine Ascents, this expedition can also serve as an outstanding ‘Denali Prep’ course – this location provides appropriate weather for the training and our guides are prepared to focus on Denali specific curriculum.

Beyond the prolific first ascentionist Padre Agostini, this mountain has been the climbing objective of many ambitious mountaineers, including the French Groupe Militaire de Haute Montagne. We are able to attempt to summit Cerro San Lorenzo by the traditional “Agostini Route” used by the first ascensionist. Mule and 4×4 support will reduce pack weight at points and augment the climber experience.

2018 Expedition

The January 2018 Expedition was a success. Climbers were thrilled with the experience – due to the scenic quality of the Aysen region of Patagonia, the opportunities for cultural interaction, and the beauty and remoteness of the mountain – and despite no summit several climbers planned to recommend this expedition to their friends next year. Also, perhaps because of no summit, at least one climber reports that she is planning on joining this expedition again next year.

For 2018 we have added four days to the expedition to increase chance of summit success, and are promoting this climb as an excellent location for preparation for Denali.

Definitely believe that this is a trip many climbers would enjoy so I hope it becomes offered annually. Absolutely special because of the remote location and spectacular landscape. Great Denali Prep course. Totally possible I will join this climb again in the future! Can’t thank all of you enough for making this trip happen. 2018 Climber

Patagnonia FAQ

Upon sign-up we will forward our famed, comprehensive confirmation package. This package will include all of the details for your trip.

What is the skill level of this climb?

Climbers should have successfully completed at least one of our Beginner Mountaineering Courses: Denali Prep on Mt. Rainier, 6 Day Baker, 13 Day Baker Cascades, 8 Day Rainier, 8 Day Alaska, 10 Day Rainier Baker, 12 Day Alaska, or have equivalent skills and experience. This climb requires proficiency in glacier travel, cramponing, and expedition camping skills. It is our goal to have similarly skilled climbers on our expeditions. For more information, please see our Cerro San Lorenzo Training page to get a sense of how to prepare and physical demands of this climb.

What is the physical conditioning for this climb?

Climbers are expected to be in excellent physical condition.

Any tips on how a climber can maximize their chances of success?

Review the Cerro San Lorenzo Training page of our website.


Our Cerro San Lorenzo climbs never exceed a 5:1 climber-to-guide ratio. Most trips have a 3:1 ratio. Our 10-person teams depart with three guides, at least one of which will be Seattle based, while typically two are local Chilean guides.

What is the best season to climb / which dates will have the most chance for success?

We have intentionally scheduled this expedition for January, the height of the austral summer, when the weather is typically most stable and sometimes even quite warm. High winds, rain, and even snow can and do occur any time of the year in Patagonia.

Will I be sharing a tent or lodging with other climbers?

On the climb, you will be sharing expedition tents. While in town during the expedition, you will share rooms, however you can pay a higher fee for single rooms. Contact our office for information on single-room supplements/

How much will my pack weigh?

Pack weights rarely exceed 50 lbs. during the approach days.

What gear will I need?

Please review the Gear List.

How does your gear rental system work?

All rental gear will be mailed to the climber prior to the climb. Climbers are expected to clean all rental gear, and those requesting rental gear must submit an expedition rental form online. Return gear to us by mail following the expedition

Any further advice on gear and using your gear list?

While all items are required, there may be times when some of the items on the Gear List may not be used (such as during warm weather or changing conditions). The Gear Lists are created by the guides to assist in having climbers be prepared to summit in any conditions.

While it is impossible for us to list all brands for certain gear, we do offer a wide variety of equipment in our Gear Shop that has been handpicked by our staff of mountaineering experts. Please feel free to call our offices with any gear questions or substitutes. Plastic boots are required for this climb.

How is drinking water treated?

Water is purified by boiling or purified using a chemical treatment like iodine or a chlorine solution such as Aqua-Mira. SteriPENS are an optional solution.

What will the meals on the expedition be like?

Meals on the trek in and at Base Camp will include fresh fruits and vegetables. Guides will prepare light-weight nutritious foods higher on the mountain.

Can I bring some food from home?

Alpine Ascents provides all meals on this climb, but you will be asked to bring your own power bars and drink mix (optional). Details will be in your confirmation package (Climber Information section).

Are there any innoculation requirements?

Not at this time. We do recommend you visit the CDC website for the most up to date information.

What is the best air route to my destination?

We will send detailed flight information to you upon registration.

When should I book my flight? Do I need to use your Travel Agent?

Fares are generally less expensive when booked early. You may use our travel agent (Charles Mulvehill 1-800-727-2157) or book flights yourself. Please note that flights booked online are often difficult to change. Please send us a copy of your flight schedule as early as possible as this allows us to book pick ups and hotels.

Where do I meet my guides?

Your guide or an Alpine Ascents representative will meet you at the airport. Look for a large Alpine Ascents sign.

What if I arrive early or depart late? Can you arrange extra night lodging? Is there a single room option for this expedition?

We are happy to make arrangements such as personalized tours, extra hotels rooms, airport pick-ups, and arrange for private rooms. Please indicate that you would like a private room on your application and we will contact you with information on single room supplement costs (for hotels only).

Are there any entry or Visa requirements?

Not at this time for US citizens.

Is there any communication while we are on the mountain?

Regular updates are posted on our website from our team while on the mountain.

Can I contact the others on the climb? How about the guide?

You can always call our offices and one of our guides will contact you, generally about one month before your trip departure. Within 30 days prior to departure, we mail a list of other team members to you.

How much should I budget for this expedition? How much cash should I plan to bring?

Please see climber information sheet in your confirmation email.

How much should I tip my guide and staff?

Guides are permitted to accept and greatly appreciate tips. Contact our office for specific guidelines for your trip. You may call our offices with a credit card or mail/fax an application with a check or credit card number.

How do I register for this expedition? What paperwork do I need to send in?

You may call our offices with a credit card or mail/fax an application with a check or credit card number. Or simply Book a Trip online.

When is the money due for this expedition? What kind of payment do you accept?

We accept MasterCard, Visa, American Express, personal checks, and Alpine Ascents gift certificates. To reserve a space, the deposit is $700. Balances are due 120 days prior to departure. Unpaid balances can result in forfeiture of trip.

What is your cancellation policy? What is your refund policy?

Note: Alpine Ascents International highly recommends trip cancellation insurance for all expeditions.

Due to the nature and heavy costs of government and operator permits, Alpine Ascents International must adhere to a stringent refund policy.

Each deposit, regardless of amount, includes a $200.00 nonrefundable registration fee.
Full refunds, less registration fee, will be provided 120 days prior to course, trek and/or expedition date.
We will provide 50% refunds 90-120 days prior to course, trek, and/or expedition date.
No refunds will be provided 89 days prior to course, trek, and/or expedition date.
All refund requests must be made in writing and be received in our office within the 90-120 day period, as stated above.
All balances are due 120 days prior to departure date unless otherwise specified.
Participants whose balances are not received by the 120-day deadline as stated above, risk forfeiture of their place on the expedition.

Note: Alpine Ascents reserves the right to waive any fees. As we offer personalized service, we will attempt to accommodate changes and cancellations when necessary, waiving certain fees when feasible.

What happens if I need to leave the expedition early?

If a climber needs to leave early, arrangements can be made with the assistance our local Base Camp support.


This is a highly recommended shortlist and we would be happy to pass on a longer reading list for those interested. These links will bounce to Amazon.com with reviews.

Death in the Andes
by Mario Vargas Llosa Penguin USA (paper)
In Patagonia
by Bruce Chatwin, Penguin USA (paper)
Labyrinths; Selected Stories and Other Writings
by Jorge Luis Borges, W W Norton & Co

I very much enjoyed the expedition. This climb would serve as an excellent prep for Denali given the need to carry loads and the interesting weather.The experience was both fun and challenging. I felt like I had a true alpine experience even without summiting. This was my 6th AAI trip and I continue to learn useful information on the trips. This climb would serve as an excellent prep for Denali given the need to carry loads and the interesting weather.


  • Denali: A Photo Essay

    by Brooke Warren Denali “The High One” is the third highest of the seven summits, right behind Everest and Aconcagua, at 20,310 feet. It is an “ultra-prominent” peak with soaring vertical relief of 18,000 feet, greater even than Mount Everest (a mere 12,000′ of vertical relief) when measured from its 2,000-foot lowlands to its lofty […]

  • Top-10 Gear Misconceptions

    Misconceptions about climbing gear can leave you wandering in the woods. In this article, we’ll look at the top-10 most common gear-related misconceptions for those newer to mountaineering, and offer some quick comments in answer. This piece was originally published in 2017, but it’s proved so helpful that we pulled it from the archives and […]

  • Improving Body Composition for Mountaineering

    by Maria Faires, RD Strength-to-weight ratio is an important key performance indicator for the mountain climbing athlete. Have you ever tried to hike up a steep trail with a heavy backpack?  The more you carry, the harder the effort. Weight matters.   A mountaineer’s performance will be enhanced by being as close to their ideal body […]

Partners & Accreditations

Alpine Ascents International is an authorized mountain guide service of Denali National Park and Preserve and Mount Rainier National Park.
© Copyright 2021 All Rights Reserved. Alpine Ascents International