It’s difficult to even begin describing this film. Right away, the title itself is misleading; calling it "Open Water 3" feels like a cynical ploy for money from the studio. It shares absolutely nothing with the first movie. I didn't connect with any of the characters and it seemed like so many errors could have been prevented. The whole experience was dull and foreseeable. Frankly, it lacked originality too. Many segments appeared to be lifted from other movies and then assembled in a clumsy fashion. The concept—shark cage diving followed by a cage failure—felt familiar; I recall seeing something similar in "47 Meters Down," which wasn't particularly good itself. Even the DVD cover looks like a blatant imitation of "Jaws," with the shark fin breaking the surface and the cage sinking, reinforcing my earlier point about “47 Meters.” The final scene was equally uninspired, tedious, and poorly performed by the actors. The sharks themselves were acceptable, though it’s clear that computer-generated imagery can simplify editing, but achieving realism isn't simple. I strongly suggest staying away from this movie; watching the original would be a much better use of your time.

Source on TMDB