what is the blue grotto resort?
Dive Site Blue Grotto Dive Resort - Williston, FL. Blue Grotto is the largest clear water cavern located in the heart of freshwater spring country in Williston, Florida. The Blue Grotto lets you dive down to a depth of 100 feet (30 meters) in crystal clear water all the way down at a water temperature of 72 degrees Fahrenheit (23 degrees Celsius) all year round.