BY PLANE: in the airport of Trapani-Birgi you should take a line bus to the city and get off at the Port, proceed indications to the Court Yard ('Tribunale')- it is situated in via XXX Gennaio.
BY CAR: in the end of the high-way proceed direction to the port, then proceed indications to 'Questura' and turn left to via 'Palmerio Abate', where you can find parking place. Behind a palace on the right side you'll find via XXX Gennaio (also with parking)