A mysterious barge spotted off the Costa del Sol this weekend has had locals and expats buzzing with curiosity.
From Malaga to Estepona and Manilva, Facebook groups have been flooded with photos, questions, and wild guesses about what the vessel was doing and why it seemed to be lingering for so long.
Wild speculation
The speculation has been almost as entertaining as the sight itself. Some joked the boat, and its huge cargo, was secretly a bridge headed for Gibraltar, destined to create a “superhighway” between Spain and the Rock. Others suggested it was part of a covert government project, or even a floating holiday home for a secret billionaire.
A mystery revealed
But as it turns out, the mystery boat is carrying a huge piece of one of Europe’s most ambitious infrastructure projects: the steel superstructure (or “tablier”) for the Anne-de-Bretagne bridge, currently under construction in Nantes, France.
According to Nantes Métropole, the steel deck is a truly massive piece: 150 metres long, 42 metres wide, and weighing around 2,200 tonnes. Built in Italy, the structure has begun a dramatic sea journey to Western France. The plan? Load the entire thing on a barge, sail through the Adriatic and the Mediterranean, round the Iberian Peninsula, before finally navigating up the Loire River to Nantes.
An extraordinary feat
Why go to all this trouble? Because once in place, the new structure will transform the Anne‑de‑Bretagne bridge into something extraordinary. The bridge is being radically rebuilt: rather than demolishing the old structure, engineers will reuse it, extending it to the west and lowering its deck to join with the new steel superstructure.
When completed (targeted for late 2027), the bridge will be the widest in Europe, with an average width of around 50 metres, more than triple its current size. But, it’s said to be ‘not just a bridge’: it’s envisioned as a green, pedestrian‑friendly “pont‑place”, a public space that encourages walking, relaxing, and enjoying views over the Loire.
Ecological ambition
One of the most impressive things about the project is its ecological ambition. By reusing the existing bridge, the developers avoid demolishing 4,250 tonnes of concrete, while saving on producing 2,600 m³ of new concrete and 1,300 tonnes of steel. The sea route also helps: transporting the complete 2,000+ tonne steel frame by barge is likely to prevent hundreds of lorry trips, significantly reducing the carbon footprint.
Expected arrival
It’s believed the recent weather, rough seas, and high winds may have slowed the convoy’s progress, leading it to pause off the Costa del Sol.
Today, it’s still visible from Manilva but the barge is preparing to pass the Strait of Gibraltar and, depending on the weather and tide conditions, is expected to arrive at the mouth of the Loire River between November 20 and December 19.
Maritime enthusiasts and those who want to continue following the barge’s journey can get updates here.
A rare sight
Living on the coast, you might expect a passing boat to be part of everyday life, but even on the Costa del Sol, this is an unusual sight on the horizon. While moving huge construction components by sea is relatively common in Europe, to those onshore it can stop you in your tracks. This one has certainly captured the interest of locals and visitors, some of whom said watching one of the greatest infrastructure projects happen in real time was exciting, even for those more used to seeing the yachts and speedboats of the Costa del Sol ports.