The oceans encompass most of the planet, but explorers have only scratched the surface of what lies beneath. What lurks below in the murky depths of the sea has an innately unsettling quality. Stories of krakens hiding in ocean waters waiting to wreck passing ships, man-eating sharks poised to pounce on unsuspecting swimmers, and sirens luring sailors to Davy Jones’ locker are commonplace in history.

Many filmmakers have tried to appeal to our preternatural fears of the unknown, and some have been wildly successful in tapping into what’s so scary about the ocean. Sometimes they use a mythological beast to play on our phobias, and other times it’s just the force of nature itself – it's clear that underwater movies about the ocean aren't going anywhere. There's no shortage of especially thrilling and scary ocean movies that dive into unexplored depths of this sub-genre. If you don’t already have thalassophobia, or an intense fear of the ocean, these best deep sea movies may change your mind.

15 'Sphere' (1998)

Director: Barry Levinson

Directed and produced by Barry Levinson, father to Euphoria’s Sam Levinson, and based on a novel by Michael Crichton, Sphere takes an A-list cast and puts them through a wringer. The film is more of a work of mind-bending science fiction than a conventional horror film. However, there are plenty of things to be afraid of, such as typhoons, jellyfish, and enormous squids.

While the film garnered mostly unfavorable reviews upon its initial release, it quickly gained a cult following thanks to its distinctive setting and an unsurprisingly charismatic Samuel L. Jackson. Sphere emphasizes the realization that humans just do not know what actually is happening miles below sea level.

Rent on Apple TV

14 'Underwater' (2020)

Director: William Eubank

Few authors have been as successful in exploiting people’s fear of the unknown as H. P. Lovecraft. Underwater is a movie that plays on Lovecraft’s Cthulhu mythos, with their version of the Great Old One resting peacefully at the bottom of the ocean until his slumber gets disturbed, to horrifying results. Kristen Stewart gives a fantastic performance as a beleaguered mechanical engineer just trying to survive with a ragtag band of scientists.

One of the best ocean thriller movies, the film is extremely suspenseful, as it practically throws the protagonist into the fray as everything around her ignites and malfunctions. Despite featuring some of the scariest sequences in a horror film in recent years, Underwater was released in the dump month of January. Despite its financial failure, the film deserves to be viewed by and unnerve a larger audience.

Watch on Hulu

13 'Open Water' (2003)

Director: Chris Kentis

Scuba diving is all fun and games until your boat leaves you behind in the middle of the ocean with no way to contact help. That is the disturbing premise of Open Water, which is made even more shocking because it is based on a true story. Things only get worse for the American couple stuck at sea as sharks surround them and exhaustion sets in.

People often have unpleasant ideas about what might occur if they get lost at sea. That Open Water was based on a tragic reality for a pair of divers makes this shark horror movie set at sea possibly the most frightening one. It effectively places the audience in the couple’s mindset as they experience the horrific reality of being at the whim of Mother Nature.

Watch on Tubi

12 'Deep Rising' (1998)

Director: Stephen Sommers

As if contagious diseases, electricity going out, and running out of shrimp aren’t worrisome enough when you’re on a cruise ship, Deep Rising shows it could always be worse. The action horror film depicts skeevy mercenaries seizing control of a luxurious cruise liner just before a monstrous kraken threatens the vessel. The ensuing chaos results in plenty of carnage for the ship as the monster unleashes a few surprises.

The Mummy’s Stephen Sommers understands not to take things too seriously, and the ensemble appears to be having a good time with the B-Movie storyline. There are some genuinely terrifying sequences in Deep Rising, and the combination of physical and early CGI effects works brilliantly to produce some truly disturbing images.

Watch on Hoopla

11 'The Reef' (2010)

Director: Andrew Traucki

The Reef is an Australian horror survival film about a group of friends whose boat starts to sink in the middle of the ocean as they’re being hunted by a great white shark. The gang sees an island off in the distance and must make the agonizing decision between staying with the doomed ship or swimming to shore.

It’s difficult not to be terrified of sharks, even though the actual harm they represent to swimmers is negligible. Still, The Reef knows that once you’re in the sharks' territory, they’re in charge, and they’ve got razor-sharp teeth to prove it.

Watch on Amazon Prime

10 'Triangle' (2009)

Director: Christopher Smith

Triangle shifts focus from monsters of the deep to the modern myth surrounding the Bermuda Triangle. Jess (Melissa George) meets up with her buddies for a lovely day out on the water until calamity strikes. Something traps Jess and her friends in a deadly temporal loop in the film, with no apparent way out.

A lively and tightly written story that both literally and metaphorically throws the audience for a loop propels Triangle. The best feature of the film is Melissa George’s outstanding performance, who really sinks her teeth into the brainy subject. This is among the best ocean horror movies that demand multiple viewings to really appreciate the puzzle pieces the writer and director layout.

Watch on Shudder

9 'DeepStar Six' (1989)

Director: Sean S. Cunningham

Many of these flicks include giant sea monsters, and it’s easy to see why in DeepStar Six. In one of the best deep ocean movies, a group of military personnel and scientists band together to defend their undersea station from attacks by a massive sea scorpion. The combined power of a leviathan and the helplessness of being confined in water makes for interesting viewing.

DeepStar Six can be sluggish at first, but once it gets going, it pushes the pedal to the metal. The film does an excellent job of depicting individuals in heightened fight-or-flight mode in the face of a crisis that is beyond the regular confines of people’s understanding of nature.

Rent on Amazon

8 'Leviathan' (1989)

Director: George P. Cosmatos

Leviathan came out at the same time as several other underwater creature features, including Deep Star Six, and features a similar plot line about an attacking sea creature. The movie makes the case for its existence because of impressive practical effects by legendary special effects artist Stan Winston and underappreciated direction by George P. Cosmatos, father to Mandy's Panos Cosmatos. Leviathan creates a stressful atmosphere filled with watery nightmares that lurk within and outside the subterranean station.

Like John Carpenter’s The Thing, which came out around the same time, critics and audiences were too eager to dismiss the film, and it, too, needs to be revisited. The ensemble cast, led by RoboCop’s authoritative Peter Weller, does an excellent job of communicating the dreadful ramifications of their situation.

Rent on Apple TV

7 'The Cave' (2005)

Director: Bruce Hunt

The Cave pushes the boundaries of thrill-seeking as a team of divers led by two brothers explore an underwater cave teeming with secrets. The movie had the unfortunate timing of releasing at the same time as The Descent, with both featuring beastly creatures attacking a group of underground explorers.

Despite a somewhat formulaic plot, The Cave does a terrific job in its own right, with stunning creature visuals that evoke fright. Several sleekly directed scenes, including a pulse-pounding cliff sequence, will make you never want to cave dive.

Rent on Apple TV

6 'Cold Skin' (2017)

Director: Xavier Gens

Although Cold Skin takes place above ground, it does an excellent job of exposing oceanic terrors. An unnamed man (David Oakes) travels to a remote island to work as a weather watcher, but gradually learns of the island’s terrifying truth. He eventually joins forces with a lighthouse keeper to repel assaults from beings emerging from the sea.

The film is very stressful and claustrophobic, particularly when the men are confined inside the lighthouse. The enigmatic creatures of Cold Skin can be both horrifying and sympathetic, but they mostly likely inspire viewers to never accept jobs in remote islands.

Watch on Prime Video

5 'Adrift' (2018)

Director: Baltasar Kormákur

Adrift is categorized as a survival drama rather than a horror or thriller film, but despite the absence of action, it has thrilling aspects that can keep the audience's attention. Directed by Baltasar Kormákur, the film is based on the actual account of a couple (played by Shailene Woodley and Sam Claflin) who set out on an ocean trip only to be slammed by a big hurricane, leaving them trapped in the middle of the sea with no means of contact, navigation or supplies.

Adrift's suspense comes from the protagonists' fight to survive in the face of a huge storm and their subsequent struggle while stuck at sea. The realistic depiction of the deadly storm inspires a sense of horror and unease, reminding audiences of the awe-inspiring power of the planet.

Watch on Hulu

4 'The Meg' (2018)

Director: Jon Turteltaub

The Meg is a sci-fi action film about a deep-sea vessel that is attacked by a giant shark that was thought to be extinct. Directed by Jon Turteltaub, the plot follows a group of scientists as they attempt to stop the titular shark before it does more harm.

While some may criticize its CGI and plot holes, its wild action sequences and entertainment value more than make up for its cheesier aspects. The Meg embraces its B-movie approach and has an undeniable ability to generate tension and a sense of danger. This is especially evident in scenes where the shark, a giant ancient predator, attacks and hunts the protagonists, who are completely vulnerable underwater.

Watch on Max

3 'All Is Lost' (2013)

Director: J. C. Chandor

Director J.C. Chandor's All Is Lost is a survival drama film about a man (masterfully played by Robert Redford) who finds himself alone aboard a sailboat in the middle of the Indian Ocean after colliding with a shipping container and starts taking on water. The movie follows the challenges he encounters as he battles the elements and attempts to fix his boat.

All Is Lost is largely about man vs nature, with little dialogue and no flashbacks. The thrilling parts in the survival drama come from the man's efforts to survive against the worsening conditions and the damage to his boat. Redford does an incredible job of portraying the struggles of isolation against someone as terrifying as the ocean.

Watch on Tubi

2 'The Shallows' (2016)

Director: Jaume Collet-Serra

The Shallows, directed by Jaume Collet-Serra, is a survival horror film about a surfer called Nancy (Blake Lively) who becomes trapped on a rock 200 yards from shore as a great white shark circles the limited area between her and safety. The film follows her as she attempts to escape and return to shore.

The Shallows does a phenomenal job of generating a stressful and tense environment. The protagonist's fight to survive while stuck on a rock with a predator watching her results in some terrifying moments. Lively's convincing acting is the true star of the movie, which deserves more attention in the niche genre.

Rent on Apple TV

1 'Jaws' (1975)

Director: Steven Spielberg

Jaws is a classic thriller that needs no introduction. Directed by Steven Spielberg based on Peter Benchley's eponymous 1974 novel, the movie follows the police chief of Amity Island, a fictional New England summer resort town, as he tries to defend beachgoers from a great white shark that has been attacking and murdering people.

Widely considered one of the most influential films ever made, Jaws is often credited for the bad reputation great white sharks still have today. It also became the pioneer of the summer blockbuster, thanks to brilliant marketing tactics and its innovative cinematic techniques. No one will soon forget its legendary theme, which likely still inspires a feeling of dread in anyone who hears it.

Watch on Netflix

NEXT: The Best, Scariest Horror Movies Set in Broad Daylight