For those bringing their own car:
From Metro Manila, take NLEX or Northern Luzon Expressway then go to Subic Freeport Zone via SCTEX.
From Manila, take a Victory Liner bus going to Santa Cruz, Zambales. Have the driver drop you off at Brgy. Pangolingan corner Radio Veritas Road. There are lots of tricycles waiting there. Take one going to Oslet Armada fish dealer compound in Bgry. Luan. Fare is Php25 per person. Then take a boat to Magalawa island.
Have a safe trip!