According to a book I have, there are water toys at the following places:
Pelican Beach (Aqua Mania Adventures)
Simpson Bay (Aqua Mania Adverntures, Westport Watersports)
Anse Marcel (Flamboyant Watersports)
Le Galion (Tropical Wave)
The Rhino Riders are at Simpson Bay-These are 2 seater inflatable motorized watercraft. You ride these and stop to snorkel and swim.
Hopes this helps a little!