The cable tunnel between Tuas Terminal Building and Pioneer Terminal Building is an essentially straight undersea cable tunnel with no further deviations throughout the 2.1 km tunnel with 2 bores except the inclusion of three vertical tunnel shafts. Each tunnel bore has 4 sets of cables which are fire-rated, oil-filled, sand packed and below the walkway.

Most of the tunnel is 2.3 m in height with the cables in 0.7 m depth of sand packed area. Each tunnel bore is approximately 5 m wide.