A rental car is the best way to see La Palma properly. The island is small — 47 km long and 27 km wide at its widest — but the roads are mountainous and winding, and driving between the capital on the east coast and Los Llanos de Aridane in the west involves either crossing the summit ridge (dramatic views, slow going) or a long coastal route to the south. Allow more time than the distances suggest.
Buses (guaguas) run between the main towns and most of the island's municipalities, operated by Transportes Insular La Palma. Service is good on the main coastal routes but infrequent in the interior and on the summit road to Roque de los Muchachos — the summit road has no regular bus service. Taxis are available in Santa Cruz and Los Llanos.
For hiking, many of the main trails are accessible from bus stops or with a short taxi from the nearest town. The national park visitor centre at El Paso can provide trail maps.