Raúl Uranga – Carlos Sylvestre Begnis Subfluvial Tunnel, Underwater road tunnel in Santa Fe, Argentina

The Raúl Uranga – Carlos Sylvestre Begnis Subfluvial Tunnel is an immersed-tube road tunnel beneath the Paraná River, linking Paraná in Entre Ríos with Santa Cándida Island near Santa Fe. Its tube sections total 2,397 m, with 270 m access ramps at each end; the roadway is 7.5 m wide and 4.41 m high, and at its deepest the tunnel lies about 32 m below the river's average level.

Construction began in 1962 and lasted seven years, with the first permanent river crossing opening on December 13, 1969. Completion allowed a direct road link between both provinces for the first time without relying on ferry service.

The tunnel was first named after Hernando Arias de Saavedra, known as Hernandarias, the first governor born in the Americas of European descent. In 2001, after eleven years of lobbying, it was renamed for Raúl Uranga and Carlos Sylvestre Begnis, the Entre Ríos and Santa Fe governors who signed the 1960 treaty and pushed the project through.

The tunnel carries two lanes of traffic, one in each direction, on a 7.5 m wide roadway with 4.41 m of clearance to the ceiling. Lighting adjusts automatically to outside conditions, and forced ventilation renews the air. Emergency phones and fire-detection equipment are installed inside the tube.

The tunnel segments were prefabricated on land, then towed into the water and lowered onto the prepared riverbed. Individual sections were then connected and sealed underwater.