There is plenty to do in Cabo without an excursion, but there is a little bit of walking to the shopping area. You can see it from the dock that you tender in to, but it's a little bit of a walk. As far as the rock formations, there are tons of glass bottom boats that will take you there for around $13.00, about half the price of the ship excursion. They are all right there as you walk off the dock, just pick one, there are a bunch of independant guys doing that. The one we took actually was leaking a little, some of the older folks on there were a little nervous about that, but I figured there were so many other boats in the water, you are really close to shore and it's not all that deep that even if we started sinking someone would rescue us pretty quickly! It lasted about 45 minutes and was a great way to start our day in Cabo, which on RCCL is one of the shortest port days. The rock formations are amazing up close. They will even drop you off at Playa Del Amour (Lover's Beach - beautiful but no facilities) and come back and pick you up later if you like. Other people on our ship told me they took a water taxi over to one of the big resorts and just hung out on the beach there.