April 17, 2026: Over the last two decades, Colombian drug cartels have been moving illegal drugs to European and Asian countries using submarines of various types. A recent innovation was unmanned submarines carrying drugs and controlled via an onboard Starlink satellite link. The smugglers back in Colombia operate these drone subs remotely. While each of these subs cost between one and two million dollars to build, each carries up to three tons of drugs, worth over $160 million wholesale. The drone subs are here to stay because they are cheap and none of the cartel members have to risk death or capture while operating the older manned submarines.

The United States has been dealing with these submersibles since 2000 because most of them were used to move cocaine to the United States. About 80 percent of the submersible traffic was in the Pacific, from South America to Mexico and, less often, to Central America. Another 15 percent operated in the Caribbean and a growing percentage of the boats were moving cocaine to Africa and Spain.

Most of these narco-subs are still semi-submersible type vessels. These are 10 to 20-meter fiberglass and wood boats, powered by one or two diesel engines, with a very low freeboard and a small conning tower, providing the crew of 3-5, and engine, with fresh air and the ability to safely navigate. A boat of this type was, since they first appeared in the early 1990s, thought to be the only practical kind of submarine for drug smuggling. After 2000 some drug gangs developed real submarines, capable of carrying 5-10 tons of cocaine. These boats were not true submarines because they did not have batteries so they could operate submerged with the diesel engine turned off. Instead, these subs used a World War II innovation, the snorkel. This looked something like a periscope, but thicker in diameter. For narco-subs, the snorkel mast was not retractable, as it is on military subs, but operated on the same principle.

In the smaller narco-subs, the snorkel proved to be more trouble than it was worth. In bad weather, waves constantly washed over the snorkel and forced its water valve to close, so water did not get into the sub. This often caused the diesel to shut down because of insufficient fresh air and too much exhaust unable to vent. The crew had a separate air supply but that supply was not sufficient to keep the diesel going, even for short periods. The snorkel was largely gone by the late 1990s. Instead, the designs of the semi-submersibles were improved by using better methods to cool the exhaust via more pipes outside the sub hull where the colder water absorbed heat before venting into the air via a curved pipe that sent the exhaust down towards the water rather than straight up. By reducing its heat signature this way, the sub reduced its vulnerability to the heat sensors search aircraft used. At that point the semi-submersible subs were very difficult to spot using radar, heat sensors, or even visually, from the air or a surface ship. With these reduced heat emissions, the snorkel was no longer an attractive alternative. The police and military have since obtained better sensors for detecting these narco-subs. The American military is a leader in this field and that is why the one percent detection rate increased to about ten percent of all narco-subs being detected and caught.

The snorkel subs also cost more than semi-submersibles and required a more highly trained crew. For a long time, there were efforts to borrow a lot of technology and ideas from the growing number of recreational submarines being built. That led to the construction of a few true subs, based on recreational subs. These proved to be more expensive to build and operate and some were still detected at sea or during construction. That meant the true subs were not sufficiently more effective to justify their higher cost. Semi-submersibles cost about $2 million to build, which takes about a year. The true submarines take several years to build and cost over $5 million.

That has led to drug gangs changing their tactics and building smaller narco-subs that carry one or two tons of cocaine at $24 million a ton so that, if one of these subs is caught, its loss is just considered a cost of doing business and not a significant financial loss.

Despite losing over a hundred semi-submersibles to the U.S. and South American naval forces, plus hundreds more to accidents and bad weather plus hundreds more to heavy use, the drug gangs have apparently concluded that the subs are the cheapest and most reliable way to ship the drugs. Early on, several hundred of these narco-subs were built and used on one-way trips to Mexico or the United States. Most of them got through. As new ones were built, their designs and durability improved to the point where the semi-submersibles were capable of multiple round-trips. Some have apparently been refurbished or rebuilt so they can undertake even more voyages.

It was these sturdier and more reliable vessels that made the trans-Atlantic routes possible. The more reliable boats also made it possible to obtain more experienced, and effective, crews. The early designs were dangerous and although high fees were paid to crew, usually operators of offshore fishing boats, it was very dangerous. Some of the early crews were recruited by threats against their families or even by kidnapping of family members. With the reusable boats more crews were making a career out of this well-paying job. Moreover, the trans-Atlantic voyages meant covering about 8,000 kilometers, which could take 15-20 days. The trips to Mexico were less than half that and the ones to Central America, or via the Caribbean, even shorter. The early trans-Atlantic voyages went only as far as some islands close to Europe and Africa but these were still about 75 percent as long as going all the way to Spain.

A detection network, run mainly by the United States, located a lot more of these cocaine subs than there were police or coast guard or navy ships available to run them all down. This was a problem that has yet to be solved. It is complicated by the fact that these aerial contacts can be lost even if you keep the search aircraft in the area for a long time so a surface ship can arrive. One possible solution to this was more international cooperation. Since the early 1990s the United States has used a special interagency group of the Departments of Homeland Security, Justice, State, and Defense, plus international ones in which over a dozen nations participate in intelligence sharing/analysis operation, called the Joint Interagency Task Force-South, to track drug smuggling from South America. After 2001 the task force became quite expert at tracking the submarines and submersibles built in South America for smuggling cocaine to North America and, in a few cases, all the way to Europe. Some of these long-range subs are apparently going all the way from Ecuador to the United States, bypassing the Mexican cartels, who have been fighting each other in a big way since 2008. Trips directly to the United States proved too dangerous and most of the narco-subs now go to Mexico or Central America.

There was always a concern that larger boats would eventually head for Europe. For years little was known about this effort, except that it existed. Then verifiable reports, from informants, electronic eavesdropping and interrogations confirmed that cocaine was coming in via semi-submersibles. It was believed that these subs would be more at risk of being lost because of an accident or bad weather than being spotted. It turned out that the new designs were even capable of making the trip and usually returning under their own power. European navies, especially Portugal and Spain's, and coast guards were alerted and began searching regularly but until 2019 had never actually caught one of these semi-submersibles. At first, it was thought that the risk of failure was so high for these trans-Atlantic narco-subs that few were built and not on a regular basis. That was not the case and the captured gangsters and overheard electronic communications indicated that the subs had become a regular method for moving the cocaine. Then the drone submarines came along and changed the drug smuggling efforts in unimaginable ways.