Do you have to book independent tours ahead of time?

We will be in Roatan in December and are not sure yet what we are going to do. I understand that Mahogany Bay will be open by then with the chair lifts running there, so we may just want to spend the day on the beach; on the other hand, we have never been to Roatan and may want to do a tour of the island. It will just depend on what we feel like doing that day. Has anyone booked an independent tour when getting off the ship, or would we have to book ahead of time?

**bump**

My husband and I are booked with Rony's Tours but my father and uncle are not booked yet and I would also like to know if they can grab a guide when they get off the ship if they do not book ahead of time.:D