Seriously, throwing a tennis ball or a frisbee while standing in water isn’t all that fun. So why not invent something that bounces on water, like a skipping stone that you can catch?
And if that is possible, why not invent a game that is fun and challenging but can be played with just the ball, no goals, nothing extra - just the ball?
The Ball The wabobaball is made of polyurethane and has a lycra coating. The mix of different polyurethanes makes the ball bounce and float on water. The ball is made to endure some rough handling, but do not bounce it on the ground or on walls etc.The ball is CE marked.

It is not recommended for use by children under 3 years.