On the windswept pampa near Arica on Chile’s northern coast, military excavators are cutting a deep trench along the frontier with Peru. The digging machines scoop out three-meter-deep channels and pile earth into embankments as stern-faced Chilean soldiers patrol nearby and Peruvian border police watch from their side of the plain.
The trenches are part of a new “border shield” pushed by President José Antonio Kast, the hard-right leader sworn in after winning 58% of the vote in December’s runoff. Kast has cast illegal immigration, drug trafficking and organized crime as existential threats to national sovereignty and has repeatedly promised tough measures. “We want to use excavators to build a sovereign Chile,” he said soon after taking office.
The work underway includes an 11-kilometre ditch on the coastal plain, a seven-kilometre cut higher in the mountains, and additional trenches further south on the border with Bolivia. The first phase focuses on short, vulnerable stretches of the roughly 1,200-kilometre frontier Chile shares with Peru and Bolivia in the Atacama Desert. Future phases call for surveillance gear—thermal and infrared cameras, sensors, radars and drones with facial-recognition systems—operating around the clock. Earlier proposals also envisaged five-metre walls in some locations.
Cristián Sayes, Kast’s regional delegate in the far north, says the project is progressing. He reported the work about halfway complete in the immediate zone, roughly six kilometres finished, and described the objective as establishing constant control to halt illegal crossings and curb smuggling, drug flows and human trafficking.
But experts and local officials point out several tensions in the plan. Illegal entries across these borders have been falling: Chile’s investigative police recorded about 2,460 attempted crossings in 2024 and 1,746 in 2025. At the same time, authorities say irregular attempts to leave Chile have surged since the change in government—nearly 500 prevented departures in Arica y Parinacota in the first four months of the year versus 33 for all of 2024, according to Prefect Inspector José Contreras Hernández.
The northern border zone bears older scars from periods of high tension: tank traps from the 1970s flank parts of the highway, and some desert stretches remain contaminated by anti-tank mines. The new trenches are already facing practical challenges of their own. Desert winds blow sand back into the cuts, and officials say the ditches will require constant monitoring and maintenance so they don’t quickly fill or erode. Two Bolivian citizens were recently detained after allegedly trying to fill in a trench to make it passable.
Kast’s government has also moved to change the legal framework. Entering Chile without authorization is currently not a crime; the administration has sent two bills to congress that would criminalize illegal entry and restrict migrants’ access to certain social security benefits.
Critics question whether short stretches of trenching will substantially reduce the movement of people, drugs or contraband along more than 4,800 miles of often-porous borders. Supporters argue the combination of physical barriers and high-tech surveillance will deter traffickers and irregular migration.
As excavators continue their work beneath the desert sky, the central questions remain practical and political: how far the construction will extend, how well it will be maintained against the elements, and whether it will meaningfully alter migration routes or simply shift them elsewhere. For now, the trenches are the visible centerpiece of a security-first approach that helped propel Kast to the presidency—but their long-term effectiveness is still uncertain.