Bastia Poretta Airport: Rent a car at the airport; it is the only genuinely practical option for a stay in Sisco. The drive is roughly 45–55 minutes via Bastia and the east-coast Cap Corse road, assuming no summer traffic. A pre-booked taxi is possible but expensive—roughly €80–110 one way—and should not be assumed to be waiting for the return journey.
Bastia ferry port: If arriving by ferry from mainland France or Italy, collect a rental car in Bastia or arrange a taxi in advance. Sisco is about 35–45 minutes north; expect roughly €55–75 by taxi. Do not rely on a convenient port-to-Sisco public-transport connection.
Bastia railway station: The Corsican rail network terminates at Bastia for this purpose: there is no train onward to Cap Corse or Sisco. Pick up a car in Bastia or take a pre-booked taxi; the transfer is around 35–45 minutes.