yes both are on water! a jet ski is like a motorcycle on water basically.u get on it and ride it like you would a motorcycle.driving driving it around in the water.kinda like a mix between a m/c and a small boat. water skiing is like snow skiing except you have a coard running from a boat you hang on and you let it pull you as you hold on to the rope while on water skies which is alot like snow skies.

Water ski - http://www.britishwaterski.org.uk/UKSki/DesktopDefault.aspx Jet ski - http://www.ncjetski.co.uk/watercraft.php

Water skiing is the type of sport you with that your body tie on boat using rope and use while using your feet or ski on the water and jumps over waves or ramp while jet skiing is the type of sport which an individual rides a jet ski and jumps over waves cowboy...

to Eliot: But Jet skiing is on water too.....Am I right?

Jet-skiing is on jets. Water-skiing is on water.