'Narco-subs': How thousands of tonnes of cocaine are being shifted across seas

Spanish authorities are increasingly on the lookout for so-called "narco-submarines", vessels carrying tonnes of cocaine that spend weeks making the journey from South America to Europe.

Spanish customs officers say that while the majority of illicit drugs entering the country arrive in containers, drug smugglers increasingly turn to more inventive ways such as submarines. Source: Channel 4

Watch Dateline's latest episode Inside Spain’s Narco Submarines on SBS On Demand.

Using submarines to smuggle drugs across the Atlantic was once thought to be a myth.

But in 2019, when the Spanish authorities captured a 'submarine' off the coast of Galicia carrying 3,000kg of cocaine, it marked a turning point, confirming that an underwater drug trafficking route from South America to Europe was real.

The first known 'narco-sub' seized in Europe is now displayed in Spain's police academy.

A 22-metre-long semi-submersible that was captured off the Spanish coast in 2019 carrying three tonnes of cocaine is now displayed at Spain's police academy near Madrid. Source: Channel 4

The 22-metre semi-submersible was piloted by Agustin Alvarez, a former Spanish amateur boxing champion. Two other crew members were his cousins from Ecuador. The three men were sentenced to 11 years in prison in 2022.

Years later, the smell of cigarette smoke and human faeces still lingers inside. The voyage from Brazil to the coast of Galicia took 28 days. The crew would take 8-hour turns to steer the vessel. The cargo, worth more than €90 million ($146 million) at the time, was stored at the front.

The 'sub' — most of it sat just below the water, making it very hard to detect — was designed for one-time use in this illegal mission. The plan was that once the drugs arrived and were unloaded onto fishing boats, the crew would open special valves to sink the vessel.

Chase at sea

Spain is now one of the main gateways of cocaine into Europe. And the port of Galicia is its main point of entry. In 2023 alone, the authorities intercepted 90 tonnes of cocaine, double that of the year before.

While over two-thirds of it was found in shipping containers, drug smugglers are finding more inventive ways. These days, Galicia’s customs officers have to work even harder at sea where they are increasingly up against elusive ocean-crossing narco-subs travelling thousands of kilometres from South America.

"Our big obsession day to day is to know everything that is in our waters," Galicia's customs chief Fernando Iglesias said.

Head of Galicia's customs Fernando Iglesias says his team has to deal with increasingly inventive drug smuggling operations at sea. Source: Channel 4

But even with helicopters and speedboats, Iglesias' team is not equipped for long chases.

"Our vessels are not designed for long distances. They are made to protect the estuaries and the entrances to them," he said.

Narco-subs are now being used frequently and globally. One known route is from Colombia to the Pacific. In November 2024, Colombian authorities seized six semi-submersibles bound for Australia as part of an international operation dubbed Orion, involving 62 countries.

The drug smuggler

Although Spanish authorities started spotting and seizing narco-subs relatively recently, local drug smuggler Luis (not his real name) says they’ve been arriving in Galicia since 1998. He claims that every month one arrives to Galicia. If he’s right, that would mean over €1 billion ($1.7 billion) worth of cocaine enters the European market a year, just from the narco-subs.

"Only about 5 per cent stays [in Spain]," he said. "The rest goes wherever there is demand. All over Europe basically."

A local drug smuggler says semi-submersibles loaded with drugs have been arriving in Galicia since the late 1990s. Source: Channel 4

In his 50s, Luis has been in the cocaine smuggling business with Mexican and Colombian drug cartels for a decade. He operates the speedboats but now also invests in narco-subs and takes a large cut of the profits.

"Sooner or later you're going to get caught. That's for sure. It's almost impossible to work without the help of the police."

The Spanish police did not respond to his allegations of corruption.

Deadly consequences

Manuel Couceiro, a priest and president of a local non-profit advocacy and support group, the Galician Foundation against Drug Trafficking, says he has witnessed the tightening grip of the South American drug cartels on Spanish society and the rise in violence those cartels are known for.

"All bad and negative things spread sooner or later. There have already been cases of settling scores and disappearances," he said.

Not only does Spain have one of the highest cocaine consumption rates in the world, but it also has one of the highest youth unemployment rates in the European Union. Lack of job opportunities adds to the lure of drug dealing.

Galician man Santiago De Dios shows a photo of his son Ismael, who went missing while transporting drugs from Colombia to Spain. Source: Channel 4

For two years, local man Santiago De Dios has been trying to find out what happened to his son Ismael who disappeared while sailing a boat with four tonnes of cocaine from Colombia to Galicia.

"There are several hypotheses," he said.

"One is that since he was the last one to join the gang, maybe as the youngest, he wanted to get paid like everyone else, and they threw him overboard out of revenge."

"Or there was an accident during the dangerous Atlantic crossing."