They both are Swim team Dramas, however the ''movie'' was a older version lets call it the original, and ''water boyy'' is a updated version, Now my opinion is that the characters were great and the chemistry was well scripted and the actors did a great job of conveying there character as if they were real people . A much more comedic feel that you can get that feel good factor while just engaging in the plot and letting it all sink in.
Similar, in the sense that both revolve around the swimming pool. water boyy has predominantly gay characters, while Dive is more like a bromance. but both I feel have there merits. Also both are worth your time to watch.