Cancellation policies differ between rentals and tours and they are described for the specific item you are booking on the INFO tab of that item.  In general, all tour reservations are fully refunded if cancelled 24 hours prior to tour departure. Full refunds are also available due to bad weather, but only if notice is given at least 1.5 hours prior to the tour.  If a tour is cancelled with less than 24 hours notice, for reasons other than bad weather, the cancellation fee will be $50.  After a tour has begun, no refunds are available.