By plane from Manila to Legaspi then by public van or private pick-up to Donsol.Private vans cost from P1500-P2000 per van, and you can get them outside the airport when you arrive. They have A/C and will drop you directly at your accommodation.Public vans are also available, but you have to take a tricycle from the airport to the bus station, then wait for the van to be full 12 people. It only costs around P80, and will drop you at the Donsol bus station in the city center, from where you have to take another tricyle to Dancalan.
Buses also are available from Manila direct to Donsol daily or via Legaspi.