If you choose to rent a boat without a guide and/or skipper, you and your passengers will be the only people allowed on board.
On the other hand, if you rent a boat with an guide, it means that the owner will be on board as a passenger, but you will be the captain.
If you rent a motorboat, you will need a licence, if it is a sailboat, some sailing knowledge will be essential.
A rental with a skipper allows you to board a boat with a professional and you do not need any previous knowledge or license. Let yourself be guided.