Federal authorities recently announced the discovery of a sophisticated cross-border tunnel connecting Tijuana, Mexico, to San Diego, California. The investigation led to the arrest of four individuals, the seizure of more than a ton of cocaine, and what officials described as a significant blow to the Jalisco New Generation Cartel.
On its surface, the story appears to be another successful drug bust. Investigators spent months surveilling a warehouse operating as a discount store called Buy 4 Less in Otay Mesa after noticing suspicious activity that seemed inconsistent with a legitimate retail operation. The business had very little customer traffic, yet employees were frequently observed moving suitcases, boxes, and other items in and out of the building. The investigation culminated in multiple traffic stops, the discovery of more than 2,269 pounds of cocaine valued at approximately $45 million, and the uncovering of a hidden tunnel stretching nearly 2,000 feet beneath the border.
The tunnel itself was impressive. According to federal authorities, it extended approximately 1,933 feet from California into Tijuana and descended roughly 55 feet underground. It contained reinforced walls, electricity, ventilation systems, and a rail system designed to move cargo efficiently through the passage. This was not a crude hole dug through dirt. It was a sophisticated transportation corridor built specifically to move narcotics while avoiding traditional border security measures.
Yet the most interesting aspect of the story may not be the drugs that were seized or the suspects who were arrested. It may be the economics.
Most people think of tunnels as smuggling routes. In reality, they are infrastructure investments. They serve the same purpose as a warehouse, distribution center, railroad spur, or cargo terminal. Their purpose is to reduce risk, improve logistics, and increase the efficiency of moving products from one location to another. In this case, the product happens to be narcotics.
When viewed through that lens, the economics become remarkable.
Estimates from tunnel investigations and border officials suggest that a basic tunnel can cost between $250 and $750 per foot to construct. More sophisticated tunnels featuring reinforced walls, electricity, ventilation systems, drainage systems, and rail networks likely cost between $1,000 and $2,500 per foot. Using those estimates, the Buy 4 Less tunnel probably cost somewhere between $2 million and $5 million to build.
That may sound expensive until it is compared to the value of the drugs seized during the operation.
Authorities estimate that approximately $45 million worth of cocaine was captured. Even if the tunnel cost $5 million to construct, the value of the seized drugs exceeded the construction cost by roughly nine times. At the low end of the cost estimate, the ratio approaches twenty to one.
Most legitimate businesses would be thrilled to achieve a 20 percent return on investment. This operation appears capable of generating returns measured in hundreds or even thousands of percent.
The most important question, however, is one that cannot be answered with certainty.
Was the $45 million shipment the first one?
The economics strongly suggest it was not.
Criminal organizations do not spend millions of dollars constructing a nearly 2,000-foot underground transportation corridor for a single shipment. The tunnel’s reinforced walls, electrical systems, ventilation equipment, and rail infrastructure indicate a project that likely required extensive planning, specialized labor, and substantial capital. Such investments are typically made with the expectation of repeated use.
Suppose the tunnel successfully moved ten shipments comparable to the one that was seized. At approximately $45 million per shipment, that would represent $450 million worth of cocaine transported through the passage.
Twenty shipments would push the total value to approximately $900 million.
No one knows the actual number. Law enforcement generally discovers tunnels only after something goes wrong. A tip is received. Suspicious behavior attracts attention. A shipment is intercepted. Someone makes a mistake.
That means the tunnels that make headlines may represent the failures.
The successful tunnels may still be operating.
History provides some support for that theory.
Federal authorities report that 99 tunnels have been discovered in the Southern District of California since 1993. The San Diego-Tijuana corridor, particularly the Otay Mesa area, has become the epicenter of sophisticated tunnel construction. What began decades ago as relatively simple dirt passages has evolved into an underground transportation network featuring lighting, ventilation, reinforced walls, rail systems, drainage infrastructure, hydraulic doors, and depths ranging from 20 to 70 feet underground.
The progression can be seen through a series of major tunnel discoveries over the past two decades.
One of the earliest examples was the famous Otay Mesa No. 7 tunnel discovered in 2006. Measuring approximately 2,400 feet, it featured lighting, ventilation systems, water extraction equipment, and an elevator-like shaft. At the time, authorities considered it one of the most advanced tunnels ever discovered. It was used to move multi-ton shipments of narcotics and demonstrated that cartels were already thinking beyond simple smuggling routes and toward industrial-scale transportation systems.
Just four years later, authorities uncovered two major tunnels in Otay Mesa measuring approximately 2,600 and 2,200 feet. Investigators seized more than 20 tons of marijuana and later alleged that roughly 50 tons may have moved through the combined operations. Using marijuana prices common at the time, the wholesale value of those shipments may have ranged from $200 million to $300 million. Those figures dwarf the likely construction costs of the tunnels.
The trend continued in 2016 when federal agents dismantled another 2,600-foot tunnel connecting warehouses on both sides of the border. The investigation resulted in the seizure of approximately 2,000 pounds of cocaine worth roughly $22 million. Analysts believe the tunnel may have operated for six months to two years before being discovered.
Then came the record-setting tunnel announced in 2020. Stretching more than 4,300 feet, it was equipped with rail carts, elevators, industrial electrical systems, drainage infrastructure, and ventilation equipment. Experts estimated that construction may have required one to three years. The tunnel was linked to seizures of cocaine, marijuana, methamphetamine, heroin, and fentanyl.
The economics of that tunnel are particularly striking. Some estimates suggest it may have transported between 20 and 100 tons of narcotics during its lifetime. Even at the low end, the wholesale value could have reached hundreds of millions of dollars. At the high end, the value could potentially have reached several billion dollars.
More recent discoveries show that the trend continues. In 2022, authorities uncovered a 1,744-foot tunnel between Tijuana and Otay Mesa equipped with reinforced walls, electricity, ventilation, and rail tracks. Investigators concluded that it was designed for industrial-scale narcotics trafficking. In 2025, Border Patrol discovered another 2,918-foot tunnel featuring lighting, ventilation, electrical systems, and a rail network. Fortunately for law enforcement, that tunnel was still under construction when it was discovered.
Authorities also uncovered an 869-foot tunnel near Nueva Tijuana in 2026 that contained evidence of narcotics trafficking, weapons storage, and communications equipment. Outside California, federal agents discovered a roughly 590-foot tunnel beneath a former KFC property in Arizona in 2018. That operation was linked to the trafficking of cocaine, methamphetamine, heroin, and fentanyl.
Taken together, these cases reveal something important. The construction costs are substantial, but they are tiny compared to the value of the products being transported.
A sophisticated tunnel may cost $2 million, $3 million, or even $5 million to build. Yet many appear capable of moving hundreds of millions of dollars worth of narcotics during their operational lives. Some may move substantially more.
The tunnel itself is not the profit center. The tunnel is the tool that makes the profit center possible.
Equally important, tunnels reduce risk. Every pound of narcotics moved through a tunnel avoids many of the dangers associated with traditional smuggling methods. Vehicles can be searched. Drivers can be arrested. Couriers can be intercepted. Border crossings can be monitored.
A hidden underground route eliminates many of those risks.
From a financial perspective, a tunnel functions much like a private supply chain. It reduces transportation uncertainty, lowers seizure risk, and creates a dedicated route between suppliers and distributors. Legitimate companies spend billions constructing warehouses, ports, rail systems, and distribution centers to accomplish similar objectives. Cartels appear to be doing the same thing underground.
Perhaps the most unsettling conclusion is also the simplest. Authorities know about the tunnels they have discovered. They do not know about the tunnels they have not discovered.
The Buy 4 Less tunnel may have cost only a few million dollars to construct. The shipment seized in connection with it was valued at approximately $45 million. If that shipment represented only a fraction of the tunnel’s total throughput, the return on investment becomes extraordinary.
The latest discovery is therefore more than a drug bust. It is a reminder that beneath one of the most heavily guarded borders in the world exists a hidden logistics network that has been evolving for more than three decades. Judging by the economics, there is every reason to believe that the organizations building these tunnels will continue digging.
IAM Editor: As a former CIA officer with a stint in counternarcotics, I can tell you that tunnels have been in use for decades and are very difficult to detect. It would not surprise me if there were enterprises within Mexico digging tunnels constantly for sale to the narcos. The ones that have been found are likely a small fraction of the ones that exist. And we would not be surprised if there were tunnels that are miles long, but with much more competent security.
Tunnel detection technology exists, but it has not been that effective.
