The main ports where there are boat rental companies are Sorrento, Piano di Sorrento, and Massa Lubrense. In these towns, you can find many boat rental and boat charter companies.
For boats with smaller engines (which include most types of boats available for rent in and near Sorrento), a boating license is not required. However, it's best to have had a bit of experience at sea before attempting to navigate by yourself.
You can take the public ferry to Capri and from there book a boat tour around the island. Prices for a private boat tour of Capri cost around EUR 140.
In the summer (July and August), you should reserve as far in advance as possible...especially for weekend dates. Otherwise, a few days ahead of time is enough.
These are tours for small groups (usually 12) on board a traditional wooden "gozzo" boat with a sundeck and small cabin. The price of this tour is quoted per passenger, and these are usually the best choice for quality/price. You can dock to visit the coastal towns, and the price generally includes beverages and a sandwich.
With an average sized boat, it takes a bit more than one hour.
In high season (from mid-June to the beginning of September), we recommend booking a boat tour to escape the heat and crowds. The cost of a day on Capri, including ferry tickets, a light lunch and a boat tour of the island, is about the same as a group boat tour.