My past time is going snorkeling,its the practice of swimming on or through a body of water while equipped with a diving mask, a shaped breathing tube called a snorkel, and usually swimfins.
Oh wow! I always wanted to go snorkeling.
cooler waters, a wetsuit may also be worn.
Is there anything else you have to use, like an oxygen tank?
You'll also need a  diving suit is a garment or device designed to protect a diver from the underwater environment
Oh ok. Do you have to take a special class or training beforehand?
Yeah ,it involves the basis of the two surface disciplines of the underwater sport of finswinning.