There are two ways to approach this isolated park. From Honolulu, take Hwy H1 west, eventually it becomes the Farrington Highway (#93). The paved road follows the coast and ends at Ka‘ena Point State Park.
From the north, use the Waialua/Mokule‘ia route. Follow the Farrington Highway (# 930) west, past Waialua and along the coast to where the pavement ends.
Both of the Ka‘ena Point trailheads are located where the paved roads end. Maps may show a dirt road going there but don't be tempted.