Within Zambales, local buses and jeepneys run along the coastal highway from Olongapo in the south up to Iba and beyond. The road is straightforward and the province is long and linear — most places you'll want to reach are somewhere along this single coastal route. Jeepneys between municipalities are frequent and cheap; tricycles cover the last stretch to beaches and resorts.
For the coves — Anawangin, Nagsasa, and Capones Island — you have to arrive by bangka boat from the village of Pundaquit in San Antonio. Boatmen at Pundaquit Beach can take you across; the boats are unscheduled and work on demand. Rates are fixed by the local cooperative and are posted at the embarkation point.
Hiring a private vehicle in Olongapo or from Manila gives you more flexibility, but the coastal highway is scenic enough to justify taking local transport. For the Pinatubo crater lake hike, the jump-off point is on the Tarlac side of the mountains, and most visitors arrange transport through tour operators in Manila or the Subic Bay area.