Do the body shapes and skin tones look familiar?
https://www.youtube.com/watch?v=kLfaqNAwO8c
I have just discovered that Japanese TV have been making a water polo tv drama filmed in the same outdoor school pool as was used to make one of the Waterboys tv series. Called the Water Polo Yankees (Suikyu Yankisu)
Have a look at this:
https://www.youtube.com/watch?v=6qypvbO4DRE
The actual drama appears not to be on You Tube etc with subtitles yet.
http://en.wikipedia.org/wiki/Water_Polo_Yankees