Situated under one of the cliffs, this century old tunnel was once a marvel. Now it is not used for any commercial purpose. This 924ft tunnel was used to pass boats carrying goods and people from Thiruvanthapuram and Kollam. The construction of this tunnel began in 1867 under the British regime and completed in 1880. It is popularly known as Varkala Turuthu.
Varkala Tunnel is a popular tourist highlight. It was a 924 ft long tunnel built in 1867 by T.Mahadeva Rao the dewan of Travancore, and took 14 years to complete. Varkala Lighthouse is another tourist highlight in the vicinity.