U.S. Southern Command- (SOUTHCOM) sponsored exercise Southern Vanguard is set to kick off in Chile, August 11-31, with a focus on high-altitude mountain warfare. Led by the Chilean Army, Southern Vanguard 2025 (SV25) will bring together mountain troops from Argentina, Chile, Peru, and the United States to train in a challenging environment.
The exercise underscores the crucial importance of military partnerships as a foundation for integrated deterrence, mutual readiness, and a shared understanding of the operational landscape.
A legacy of partnership
Southern Vanguard is an annual exercise organized by U.S. Army South (ARSOUTH) to enhance relationships, promote mutual military readiness, and increase interoperability among regional partner nations. While conducted at the tactical level, the exercise series has a growing operational impact at the Army-to-Army level.
The series began with a pilot program in 2021. The first iteration was a command post exercise (CPX) conducted in Portillo, Chile. It involved the U.S. Army’s 2nd Brigade Combat Team, 10th Mountain Division, and the Chilean Army’s 3rd Mountain Division, who worked together to practice “cold weather, survival, medical evacuation, movement and maneuver, and mountain warfare training.”
This foundation was built upon with the second iteration, a CPX held in Brazil in late 2021. The exercise, which merged the Brazilian Army’s Land Operations Command-sponsored Combined Operations and Rotations Exercise (CORE) 21 with Southern Vanguard, was a landmark event, described as a “first of its kind” for not only committing the largest U.S. Army conventional force ever to train in Brazil, but also for successfully integrating separate national exercises into one. The third iteration, SV23, was conducted in Colombia, with observers from the Brazilian and Peruvian armies.
Most recently, the fourth iteration, SV24, took place in Brazil and was once more combined with the Brazilian Army’s CORE, with a focus on jungle operations. This consistent history of joint training demonstrates a long-term commitment to building a cohesive, capable regional defense network.
A new chapter in mountain warfare
SV25 is set to strengthen combat capabilities in a location specifically chosen for its demanding environment. According to Chilean defense analyst Guillermo Holzmann, the exercise “takes advantage of the geographical, topographical, and geological conditions of the Andes mountain range, particularly in the Antuco area, which has excellent rock formations, steep ascents, low temperatures, and significant temperature variations during the day and night.” These unique conditions, he added, “test the operational continuity capabilities and the clothing and equipment used, which allow for the mobility required for very precise tactical deployments.”
The training agenda includes an initial integration, planning, and preparation phase culminating in a field exercise where troops will apply their skills in a demanding operational environment. The exercise is particularly meaningful for the U.S. Army’s 10th Mountain Division, which specialized in combat in rugged terrain since World War II, as it provides an opportunity to “return to the Division’s roots.”
Partnerships as the ultimate deterrent
Beyond the tactical training, Southern Vanguard is a strategic tool for fostering lasting security and stability in the region. Former ARSOUTH commander, U.S. Army Major General William L. Thigpen, during his closing remarks for SV24, emphasized the strategic imperative of cooperation, stating that “working together is our greatest advantage when it comes to long-term competition with adversaries that seek to undermine our shared values and security.”
This sentiment was echoed by U.S. Army Colonel Chris Jhones, an SV25 exercise director, who, during a recent planning conference, said that SV25, “is not just about training at high altitudes, but about forging relationships, increasing interoperability, and preparing our forces to operate effectively in any environment.” Col. Jhones added that the challenging terrain in Antuco is “ideal for developing the skills required for future coalition operations,” highlighting a shared vision of a capable and unified force prepared for a wide array of contingencies.
A multilateral approach
The inclusion of multiple partner nations in SV25 is a deliberate and strategic decision. “The fact that two countries, Peru and Argentina, have been invited this time is consistent with what the United States is doing to ensure interoperability among different forces,” Holzmann said, explaining that it also aims to enable forces to deploy “defensive or deterrent military capabilities” as well as those “geared toward rescue, disaster relief, or extreme situations, which require a high level of military preparedness.”
This convergence in planning, according to Holzmann, is crucial “so that these specialized units can act together in any scenario where they are needed.” The exercise also serves as a tangible demonstration of a trust-based partnership among regional allies.
From reciprocity to readiness
This spirit of partnership that defines the exercise is built upon a history of reciprocal learning. For instance, this was recently demonstrated between Chile and the United States in July 2024, when U.S. and Chilean Marines came together for integrated cold weather training in Punta Arenas, Chile. During the training, participating Marines learned from each other while conducting bilateral squad-level operations, live-fire and maneuver ranges, and night-vision optic training in Chile’s mountainous terrain.
During a previous engagement in 2023, a U.S. platoon trained in mountain movement and survival with the Chilean Army. The experience was highly valued, with U.S. Army Sergeant Manuel Elías stating at the time, “We came here because the [Chilean Army] Mountain School is the best in this specialty, and we are ready to learn from them. Their instructors are excellent professionals.”
This reciprocal learning and exchange of tactics are at the core of exercise Southern Vanguard. It allows for a deeper understanding of each military’s doctrine and capabilities, which, as Holzmann pointed out, creates “convergence in planning” for a “timely, rapid support with a clearly efficient deployment.”
Ultimately, Southern Vanguard is more than a single training event; it is part of a long-term commitment to building a robust, unified, and ready regional defense network. The history of the exercise demonstrates a progressive and adaptive approach to partnership, where the United States and its allies work together to build a foundation of trust and interoperability that serves as the most effective deterrent against threats and the best prepared response to crises.
