We had a wonderful time exploring the caves and coast with Simon as our guide. While we booked the group tour, we got lucky and ended up being the only boat in the 11:00 time slot. The water was busy but the guides do a good job of managing the number of boats in a cave at one time. Simon was super helpful in coaching us through navigating the waves and ensuring our safety before bringing us into a cave. Definitely recommend as a must-do activity while in the Algarve!