Has anyone done the Sail and Snorkel excursion on Carnival in Cabo?

My family is considering this excursion but we have never snorkeled before and are not especially good swimmers. Do they give sufficient instruction for a first timer and do you wear a life jacket? Can anyone tell me more about this?

To be honest, I won't chose Cabo as a snorkeling location. Have snorkeled all over the world, and the Mexican Pacific coast is a long way from the top of our list for snorkeling. Water conditions (visibility, temps and fish) just aren't that great.

I would save your first snorkeling adventure for a better location, like Hawaii, or any of a number of great locations in the Caribbean.