Online directions:

Google Maps page

Mapquest page

From San Francisco:

Take I-280 South toward San Jose.
Take the Highway 35 West exit toward Highway 92 West, following the sign for Bunker Hill Dr/Half Moon Bay. Merge onto CA-35/Skyline Blvd, then turn right (west) at Highway 92. When you get into Half Moon Bay, turn left at Main Street.

From San Jose:

Take I-280 North toward San Francisco.
Take the Highway 35 West exit toward Highway 92 West, following the sign for Bunker Hill Dr/Half Moon Bay. Merge onto CA-35/Skyline Blvd, then turn right (west) at Highway 92. When you get into Half Moon Bay, turn left at Main Street.

Parking:

Parking is FREE in downtown Half Moon Bay! Public parking lots are available on many downtown blocks, both east and west of Main Street.  Additionally, free 2-hour parking on the street is available on every street in downtown Half Moon Bay.