We really recommend you book in advance.  Tours in high season regularly sell out on the day of the tour and sometimes before, while in low season tours will be cancelled if no-one has booked by the previous day.  So if you just turn up you run the risk of there being no tour running in low season, or no space on the tour in high season!  

But if you do risk it we will happily bring you on the tour if there’s space, just make sure to have cash to pay the guide at the end of the tour!