I bought tickets online ahead of time for the 8:40 ferry to Positano on NLG website. Unfortunately, the day were were in Salerno the ferry to Positano was not running. They are doing some repairs to the dock. We did take the ferry to Amalfi instead. It was very easy. We left from Molo Manfredi which was right outside the cruise terminal. When we came back we were dropped off at the Piazza Concordia. The walk back to the ship is not bad but it may be bad in the heat of August.