Brazil & Southern Cone - October 2025

The idea of building a structure across the estuary that separates the coastal cities of Guarujá and Santos in the state of São Paulo has been around for nearly a century but never came off the drawing board because of a host of technical, political, and financial problems. Now these challenges seemingly have been overcome with the successful tender on 5 September for the construction of a tunnel under the waterway leading up to Santos, Latin America’s largest commercial port.

The Santos-Guarujá tunnel project will utilise immersed tunnel technology, a construction method where prefabricated segments are sunk and joined underwater. This is expected to provide the solution to the challenging subsoil. An excavated tunnel would have had to be very deep and 1,200m longer due to the type of soil in the waterway, and a bridge would not provide the necessary height for ships to clear. The immersed tunnel was a solution for a complex traffic flow involving cyclists and supramax ships in a densely populated city.

The project will also benefit from the technical know-how of the consortium that made the convincing offer for the tender – Portuguese construction company Mota-Engil in partnership with China’s CCCC, which has experience with complex projects that involve bridge-tunnel systems with immersed tube tunnels, such as the Hong Kong-Zhuhai-Macao Bridge and the Shenzhen-Zhongshan Link.

The state government of São Paulo and the federal government have agreed to split the project’s cost of R$6.8bn (US$1.3bn), overcoming political differences between left-wing President Luiz Inácio Lula da Silva and right-wing governor Tarcísio de Freitas, who could both face each other as rival candidates in next year’s presidential race. At the time of writing, neither has confirmed plans to run in the 2026 election, but opinion polls have ranked Lula and De Freitas as among the strongest potential presidential contenders.

But it has been an uneasy partnership between Lula and De Freitas, with both sides claiming to be the intellectual authors of the project and failing to give the other credit. At one point President Lula considered putting the entire project under control of the federal government, according to national daily Folha de São Paulo. But in the end, he backed down and declined to attend the public tender, sending Vice President Geraldo Alckmin in his place.

Win-win

What convinced both leaders to play ball is that the project is a winning proposition that benefits local residents and maritime shipping alike. Traffic is intense between the port city of Santos on the island of São Vicente and the city of Guarujá on the island of Santo Amaro. Currently 23,000 people per day must take a 20-minute ferry ride or drive a 30km detour for 50 minutes. The tunnel, which will be accessible to pedestrians, cyclists, motor vehicles, and a tram, is expected to reduce that time to two minutes.

Unlike other major infrastructure projects that have been held up because of red tape, the tunnel obtained a previous environmental licence from the state regulator Companhia Ambiental do Estado de São Paulo (Cetesb). However, it has yet to obtain other construction and operation permits. In fact, there are numerous potential pitfalls for the project, including geological surprises, massive coordination challenges that may require temporary closures of the port’s access channels, and expropriations needed on either side to build access ramps and shafts.

Other port projects

Other public works that will be tendered by the ports and airports ministry in the remainder of the year will pave the way for investments of R$20bn (US$3.6bn). They include new terminals and improvements in the access canals at Santos and Paranaguá ports. The Paranaguá port, in the state of Paraná, is Brazil’s second largest commercial port behind São Paulo’s port of Santos. The federal government stated in August that the criteria for the Paranaguá canals project will serve as a model for the public tenders of other upcoming port infrastructure works, such as access canals in ports like Santos and Itajaí, in Santa Catarina state.