longest Tunnel in Philippines At 300 meters, Kaybiang Tunnel is the longest road tunnel in the Philippines. The tunnel bores through Mt. Palay-Palay, and connects Ternate, Cavite to Nasugbu, Batangas. Right after exiting the tunnel at the Nasugbu side, travelers have a seaside view of islands Limbones, Carabao, and El Fraile.