Tom Ewart Smith
SPAIN is facing a growing maritime threat as drug cartels embrace a new tool in the smuggling trade: the narcosub.
These low-profile, semi-submersible vessels – often built in South America – are capable of transporting tonnes of cocaine across the Atlantic undetected, delivering their cargo to the southern coast of Spain via what experts now refer to as the ‘Cocaine Superhighway’.
The Guadalquivir River has become a key route for trafficking networks bringing drugs inland from the Atlantic.
Officials say the surge in semi-submersible use, combined with increasing local collaboration, has made Spain’s southwest coast one of Europe’s most active narco zones.
Law enforcement agencies have tracked a steady increase in narcosub activity, much of it linked to West African and South American supply lines.
Today, the subs are usually deployed off the Iberian Peninsula’s southern coastline, remaining in international waters – often near the Bay of Cadiz – until high-speed boats arrive to collect the cargo.
The final stretch is typically made via the Guadalquivir, whose network of tributaries and tall reed-lined banks provide natural cover for traffickers.
Local pilots familiar with the river’s shifting currents and narrow channels play a key role in this phase of the operation.
According to investigators, these pilots act as gatekeepers, guiding smugglers through areas like the Brazo de la Torre – an isolated stretch with only seven kilometres of navigable water, but crucial for access to inland hubs.
Towns such as Sanlucar de Barrameda, Chipiona, and Trebujena have seen increased law enforcement presence as authorities respond to the growing flow of cocaine through the region.
Trebujena, in particular, has drawn attention following the arrest of a high-profile trafficker known as ‘El Tarta,’ whose network was dismantled in a major police operation earlier this year.
Officers recovered hundreds of kilos of hashish, tens of thousands of litres of fuel, speedboats, stolen vehicles, and surveillance equipment.
What makes the narcosub threat especially difficult to counter is the technology behind it.
Many of the vessels are built in Brazilian shipyards and designed for single use, intended to be scuttled once their cargo has been delivered.
Some are even operated remotely, without any crew onboard – further complicating interception and prosecution.
Until recently, Spanish law did not explicitly define the use or construction of narcosubs as a serious crime.
But a reform to the penal code has changed that, giving prosecutors new powers to go after those involved in both the design and deployment of these vessels.
Despite these legislative changes and a growing number of joint operations involving Spanish, Portuguese, American, and British forces, experts warn that traffickers are adapting faster than authorities can respond.
One recent interception – over 900 kilometres southwest of the Azores – marked the deepest offshore seizure of a narcosub to date, highlighting just how far these operations can reach.
“They’ve realised they can build them bigger and bigger – like the last one near the Azores. They pack in tons of cocaine, a week’s worth of food, loads of fuel containers, and four or five guys willing to risk their lives for a few thousand euros,” one senior officer told Diario de Cadiz.
As criminal networks continue to invest in covert maritime logistics, Spain’s role as a major gateway for cocaine into Europe is only expected to grow.
Whether via land, sea, or now, beneath the surface, the smuggling trade continues to innovate – and Andalucia remains right at the centre of it.
