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Colossal tunnel of almost 14 km under the Andes aims to connect Argentina and Chile 365 days a year with two parallel galleries, reducing snow blockages, accelerating exports, and transforming South American trade.

Author profile image Alisson Ficher
Written by Alisson Ficher Published on 25/07/2026 at 22:12
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Binational project plans two tunnels under the Andes to connect San Juan, Argentina, to the Chilean region of Coquimbo, with the promise of continuous operation throughout the year, although the project still depends on updated financing, bidding, and schedule to move forward.

Planned as a permanent road link between the Argentine province of San Juan and the Chilean region of Coquimbo, the Agua Negra Tunnel would cross the Andes through two independent tunnels, each approximately 13.9 kilometers long.

By reducing reliance on the current high mountain pass, often affected by snow and severe weather conditions, the proposal would allow cars and trucks to circulate year-round between Argentina and Chile, with greater operational predictability.

Still, the underground passage has not been built, and an evaluation by the Inter-American Development Bank recorded that the resources linked to the Argentine operation were canceled after years without the initially planned execution having started.

Two tunnels to cross the Andes

According to the design released by the IDB, the project would have one tunnel for each direction of travel and would adopt an underground route capable of reducing the road crossing distance between the two countries by about 40 kilometers.

With the connection between San Juan and the Chilean coast, producing areas in the South American interior would be closer to Pacific ports, creating a logistical alternative for cargo destined for both regional trade and external markets.

According to the bank, the new passage would eliminate existing curves on the mountain route and reduce travel time, while continuous operation would increase the predictability of international transport, currently vulnerable to seasonal closures and weather restrictions.

Located at about 4,780 meters above sea level, the Agua Negra Pass operates only part of the year, a situation that limits the regular flow of vehicles and supports the case for a permanent underground connection.

Bioceanic corridor and logistical impact

By creating a more stable route between the Atlantic and Pacific oceans, the project could facilitate travel planning, deadlines, and costs for carriers crossing the border, reducing some of the uncertainties associated with the high mountain route.

Additionally, the Agua Negra Tunnel was presented as a complement to the Cristo Redentor system, the main road link between Argentina and Chile, with the potential to absorb part of the concentrated traffic in this passage during congestion or temporary closures.

For Argentine regions far from the Pacific, access to Coquimbo would shorten the path to Chilean maritime terminals and favor exports destined for Asia, although this outcome depends on the construction of the tunnel and the planned road connections in the corridor.

In its projections, the IDB also linked the project to the logistical integration of Argentina, Chile, Brazil, Paraguay, and Uruguay, but these effects remain conditioned on the implementation of the crossing and, so far, have not been produced in practice.

Approved financing did not become a project

In 2017, the Inter-American Development Bank approved an initial operation of US$ 280 million, divided into US$ 130 million for Argentina and US$ 150 million for Chile, within an estimated cost of US$ 1.5 billion.

At that time, the resources were to be allocated to technical preparation, temporary accesses, portals, and the first segments of the infrastructure, while the governments of the two countries would conduct the necessary institutional steps to enable the binational project.

The expected progress, however, did not materialize, as the IDB report on its program in Argentina between 2021 and 2023 recorded the full cancellation of the US$ 130 million that had been reserved for the country.

The same assessment reported that the products of a technical cooperation linked to the project lost their purpose because the tunnel was not built, leading to the redirection of the corresponding resources to other operations conducted by the bank.

Due to this history, the initiative cannot be presented as a project in progress or infrastructure close to becoming operational, as there is no new financing contracted, active bidding, or updated executive schedule in the consulted sources.

Resumption depends on new definitions

Designed to tackle the high altitude of the Agua Negra Pass, the solution would reduce the exposure of transport to weather conditions that restrict the use of the existing road crossing and interrupt part of the circulation during certain periods of the year.

Even with the logistical potential attributed to the initiative, the Agua Negra Tunnel remains a project of integration between San Juan and Coquimbo, without the anticipated commercial, tourist, and operational benefits having been effectively produced.

A potential resumption will need to gather confirmed financing, contracting process, and public timelines before it is possible to estimate when the passage could accommodate vehicles or concretely alter the commercial flows between the South American interior and the Pacific.

With almost 14 kilometers planned under one of the largest natural barriers of the continent, when will Argentina and Chile be able to transform the Agua Negra Tunnel into a connection truly open for 365 days a year?

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Alisson Ficher

A journalist who graduated in 2017 and has been active in the field since 2015, with six years of experience in print magazines, stints at free-to-air TV channels, and over 12,000 online publications. A specialist in politics, employment, economics, courses, and other topics, he is also the editor of the CPG portal. Professional registration: 0087134/SP. If you have any questions, wish to report an error, or suggest a story idea related to the topics covered on the website, please contact via email: alisson.hficher@outlook.com. We do not accept résumés!

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