The Ruta de los Volcanes is probably the most travelled of all the routes on La Palma. It runs along the ridge of the Cumbre Vieja from the Refugio del Pilar to Los Canarios (Fuencaliente) through a unique volcanic landscape and can be reached by taxi from El Paso, Los Llanos de Aridane or San Isidro. From Los Canarios there are buses to Santa Cruz de La Palma and buses to Los Llanos de Aridane. See timetables.

Another alternative is to take the bus from Santa Cruz to the entrance of the tunnel of La Cumbre, follow the track for about 100m and go up the firebreak (bad and steep) until you reach the GR 131 and continue to the refuge of El Pilar (6 km and a difference in altitude of 350m).

More information: https://es.wikiloc.com/rutas-senderismo/la-palma-ruta-de-los-volcanes-el-pilar-los-canarios-30902965