The Ceneri Base Tunnel (CBT; Italian: Galleria di base del Monte Ceneri ) is a Swiss railway base tunnel in the canton of Ticino . It passes under Monte Ceneri between Camorino in the Magadino Flat and Vezia near Lugano ; it bypasses the former high-altitude rail route through the Monte Ceneri Tunnel. It is composed of two single-track tunnels, each 15.4 km (9.6 mi) long. It is part of the New Railway Link through the Alps (NRLA) project for faster north-south rail links across the Swiss Alps .

An exploration tunnel near Sigirino was excavated between 1999 and 2003 to gain geological data on the rock formations at the Ceneri Base Tunnel's level. Based on those data, it was decided to excavate most of the tunnel with traditional blasting methods and only drill a small part using a faster tunnel boring machine (TBM).