Post Office – Port William – Opening Hours & Branch Details Visit your local Post Office branch at 5/9 The Square, a 0.05 mile distance west of the centre of Port William (near to Square). The branch serves customers from the areas of Monreith, Mochrum, Castlewigg, Port William Town Centre, Whauphill, Clone Point and Sorbie. Today’s (Friday) opening hours are 7:00 am until 7:00 pm. On this page you may find all the beneficial information about Post Office Port William, including the operating times, branch location or phone details.