Deep Blue Sea 3 is the third film in the Deep Blue Sea franchise.
Set after the events of the second, the film focuses on Dr. Emma Collins and her team who are spending their third summer on the island of Little Happy studying the effect of climate change on the great white sharks who come to the nearby nursery every year to give birth. Along with the last two inhabitants of this former fishing village, their peaceful life is disrupted when a "scientific" team led by her ex-boyfriend and marine biologist Richard show up looking for three bull sharks who we soon learn aren't just any bull sharks.
Deep Blue Sea 3 provides examples of:
- All There in the Manual: In the bonus features for the Blu and digital, concept art for one of the main sharks lists its name as Cyclops.
- Arc Welding: This film retcons that Deep Blue Sea 2 was a sequel to the original, rather than a remake, by explaining that whilst the precise procedural data and only samples of the miracle chemical were lost with the original complex's destruction, the basic information behind the experiment remained in the US patent office and other governmental files. Charles Durant, the Mad Scientist from the second film, found this information and attempted to put his own spin on it, leading to the events of the second film.
- Big Bad: Lucas.
- Big Damn Heroes: Sally the great white actually saves Emma from one of Lucas' thugs.
- Continuity Nod: Carl Durant and Akhelios from the last film are brought up as well as the three bull sharks being Bella's offspring. It also ties all three films together by stating that Carl had gotten his hands on the work of research lab from the original film.
- Disney Death: Miya.
- Even Evil Has Standards: Whilst he has his own greed-based hopes to exploit Bella's offspring, Richard does want to get them contained with minimal loss of life. When Lucas makes it clear he intends to just kill the civilians to cover up the sharks' existence, he's horrified. Ultimately, he gives Lucas a "The Reason You Suck" Speech and tries to defect to join the heroes. Unfortunately, he gets killed making the attempt.
- Final Girl: Played With as Emma survives but so do Miya and another female character while none of the male characters make it to the end .
- Fluffy the Terrible: A great white shark featured in the film is called Sally.
- Green Aesop: The film isn't shy about bringing up the horrors of global warming every 10 minutes.
- Half the Man He Used to Be: Twice.
- Heel–Face Door-Slam: Richard quickly sides with Emma and the others at the start of the climax only to get unceremoniously killed off by one of the bulls, which grabs him in midair as he jumps off the ship.
- Heroic Sacrifice: Shaw sacrifices himself in order to kill two of the sharks via explosive rounds.
- Irony: Richard tells Lucas he'd rather die than be like him before he jumps off the ship. He's almost immediately halfway swallowed by a breaching shark and dragged below.
- It Can Think: Like the sharks in the original, the bull sharks in 3 are problem solvers and are able to recognize threats. Richard even manages to get them from backing off from attacking their vessel by threatening one of their brothers.
- Mythology Gag: The running gag of people giving inspirational speeches before immediately getting eaten by sharks happens not once, but twice here.
- At one point, the sharks swim backwards to get away from a mine Emma holds in a similar way that the sharks in the original did when Carter aimed his harpoon gun at them.
- A villain's head is bitten off by a leaping bull shark exactly like a scene from the second film.
- The shot of the two sharks ripping Earl's decapitated body in half is an almost scene for scene recreation of Carter Blake being ripped in half by Makos in the original.
- The lab from the original is brought up and tied into the lab from the second.
- A shark can be seen in the distance ripping a character apart in a shot similar to one from the original where the lead Mako kills Susan, shaking and ripping her apart.
- The ending initially seems to simultaneously invoke and subvert the ending of the original film, with two characters surviving, one black and one white. The twist is that both survivors are women here, whereas they were men in the original film. And then a third survivor, the Asian girl Miya, turns up at the last moment.
- Men Are the Expendable Gender: All the deaths are men, and all the male characters die. Ironic when one remembers that all the female characters died in the original, leaving only two male characters alive.
- Off with His Head!: One character is offed this way, courtesy of a leaping bull shark.
- Redemption Equals Death: Richard calls out Lucas for planning to murder the civilians for profit and decides to side with the civilians, including his ex-girlfriend... but as he jumps from the ship, intending to swim over and join them, a mutant bull shark breaches and grabs him in mid-air, devouring him.
- Rule of Three: There are three bull sharks in the film. Also, there are three survivors. If you discount Sally the Shark.
- Sudden Sequel Death Syndrome: Bella, the main shark antagonist from the second that survived a flare to the face at the end of that film, is found dead in a net in this one. That doesn't stop three of her pups though.
- The Walls Are Closing In: The final shark is killed this way via trash compactor, with its head being squeezed until it pops.
- Threatening Shark: The bull sharks. Surprisingly averted in the case of Sally, a great white who is portrayed positively, saves Emma from a villain, and survives through the entire movie, seeing Emma and the survivors off.
