The Sentiero Azura (Blue Trail) is the main trail that links the five villages, although unfortunately the southern part of the trail from Corniglia through Manarola to Riomaggiore is under repairs as of the time of writing. The section from Riomaggiore to Manarola is expected to reopen in 2021 and the Manarola to Corniglia “Via dell’Amore” portion is intended to be opened again in 2022.
The entire Sentiero Azura, an old mule trail, is a total of 12 kms long and boasts spectacular views. You will need some level of fitness to do the trail, given that each section takes around 2 hours, and you will need to take plenty of water if doing it during the summer months as it can get quite hot! (Note also that there is a fee to use the Blue Trail.)