The Devil's Mouth follows a group of friends who find themselves trapped in a system of pitch-black caves with a vicious, hungry bull shark. The movie, which premieres on Prime Video on July 29, blends suspense and underwater thrills, delivering an immersive survival experience and fun summer adventure.
Set against the stunning backdrop of Thailand's coastal caves, the film transforms a natural wonder into a claustrophobic nightmare where danger awaits around every corner.
Jeff Wadlow (Kick-Ass 2, Truth or Dare, Imaginary) directs. Meanwhile, Kathryn Newton (Abigail, Ready or Not 2: Here I Come, Ant-Man and The Wasp: Quantumania) leads a cast that also includes Lana Condor, Nico Hiraga, Gavin Casalegno, and Tommi Rose.
We recently spoke with Jeff and Kathryn about shooting The Devil's Mouth in Thailand, utilising a mix of practical and visual effects, and what it was like for the latter to get in the water and battle a shark. They also discuss their collaboration, and Kathryn—a bona fide Scream Queen at this point—explains what drew her to this survival horror.
The actress also comments briefly on returning as Cassie Lang in Avengers: Doomsday, revealing that she's "grateful" and "excited" to be part of the massive ensemble (as you might expect, she dodged our question about the Young Avengers).
You can check out our full interview with Jeff Wadlow and Kathryn Newton on The Devil's Mouth below.
Kathryn, you've more than earned that Scream Queen status these past few years, but what was it that drew you to a survival horror like The Devil's Mouth?
Kathryn: We had a really good script. It was a Black List script. It was a tour de force character that I really didn't want to play. I really wanted to play Lana Condor's character. I thought it would be more fun. I thought Sarah was a harder character to make. I don't know. I just didn't want to do it. But I wanted to use my physicality. It was a great ensemble. Every role was amazing. So I could have been any character and been really happy, but I thought that my physicality would have been really appreciated. And that's really all I want to do — push myself. So I was drawn to that. I was drawn to the opportunity to be underwater and really rock climbing. I love rock climbing, and I thought that was cool. I thought, "Okay, this might be fun." And it was incredible.
Jeff, I've got to ask about the shark. How did you approach bringing that to life in terms of the practical and visual effects? And were there any other movies that inspired how you approached using it almost as a villain of the story?
Jeff: You know, I'm a big believer in practical effects. If you look at all my movies, I try to have as many practical effects as possible. I like the reality that they create, but I'm also not scared of using modern tools and CGI and digital tools. To me, it's all about hiding the seams. I just don't want the audience to see where we transition from one to the other. And so there was a lot of exploration done with the shark about what we could do practically, what we couldn't do practically, what we wanted to do practically. Ultimately, the shark is largely digital, but I did a lot of things on set to help the actors understand the shark as the villain.
I had the art department build a life-sized version of the shark we designed. And the shark we designed looks quite different from an actual bull shark because I wanted it to have this really muscular kind of neck so you understood that it was going to beat you with its skull, which is something that bull sharks do. They strike their prey with their head to stun them. So I built the life-size shark. I put it in my office. So whenever we were talking about the shark or rehearsing a scene, I'd be like, "Look how big that thing is. That's the size of the shark." Just constantly trying to remind people. We had a fin on an RC boat that we would pilot around the five-foot [water].
Kathryn: That was fun. I've played with it a couple times.
Jeff: Yeah. Because we had a sound stage that flooded with five feet of water, we would then have the boat going around the sound stage so people knew where the shark was. We also did things that have never really been done in shark movies before. I had this idea that I really wanted the shark to maul their victims in this film. Not just bite them, eat them, and take them down, but really maul them into the rocks. I wanted this one attack to be more brutal than the bear attack in The Revenant. So we used winches to actually move the actors around. That was quite practical. Actors were being jerked and yanked and thrown all over the place. Sometimes they're stunt doubles, sometimes it was the actual actors. So just every opportunity I had — I guess the short answer to your question is try to use some practical element to complement the CG so that you couldn't necessarily find the seam.
Kathryn, obviously you've played a superhero, so you're not exactly a stranger to action, but just how much more physically demanding is it for you to be working in the water and facing off with a CGI shark like Jeff describes?
Kathryn: I think every movie you make is like your first movie every time. Doesn't matter how many movies you've made. This one is something none of us understood really. We had an idea, but then you get there, and the camera's bobbing around, and you can't hit your mark. You have to relearn everything every day. So this one tested all of us, but also I think I rose to the occasion. I think we all did. And I wanted the challenge. I think I was looking for something like this. So it was nothing like any other action film I'd ever done because you're right, I was in the water. I had to learn how to be calm and to also let go and really be present. You can't think too hard about anything. And yet we had so much to think about in this movie. It was about letting go and just losing myself in Lana Condor's eyes, which was easy.
Thailand almost becomes a character in the movie as well. So what was it like for you both filming there? Were there any unexpected challenges or maybe advantages that came with heading there to make this movie?
Kathryn: Well, I remember one day Jeff was giving direction to the camera, and we had to translate everything. Or for me, my hair and makeup team — they didn't speak English. So we just felt beauty. We understood glam in an inherent way. Things like that you don't think about.
Jeff: Thailand is definitely a character in the movie, and that was kind of part of the mission. I didn't want the audience to ever say, "Why would you ever go on this trip?" So part of that involved really selling the trip. The first half an hour of the movie, I wanted it to be beautiful and expansive and lush, and Thailand brought all of that. The only real challenge was how do we cram it all into the first 30 minutes? I was trying to shoot things that the production team was like, "We don't have the time or money to do." I was like, I want to do it all. So I was really trying to make Thailand a big part of the film, and I wanted to shoot in real caves so that you believed in the caves when we got into the stages. To do that, I had to make sure that Thailand felt like a character in the film. That's the best way to say it.
Kathryn, on a different note, you got to announce that you'll star in Avengers: Doomsday this December. You showed off the chair. So is there anything you can tease about that experience? I know a lot of fans were really hoping to see those Young Avengers together, but anything you can say about that one?
Kathryn: I guess I can say that I'm in it now. [Laughter]
Jeff: Josh, it's not going to happen. I'm a geek. Don't you think I've asked her this question already? She won't even tell me off the record.
Kathryn: No. I'm so excited, though. I'm so grateful to be a part of it. You have no idea. I am so excited to be in it.
There are so many intense scenes in this movie. So when you're shooting those big high-stakes moments, do you lean a lot on each other as director and actor to really make sure you get to tell the story in the way that you both want to when you're working together?
Kathryn: Definitely. I just liked that Jeff really knew what he wanted, and it was easy to talk to him about what he needed and understand. And in that little box of what we need, I was able to push it. And I think he really knew what I was capable of too. And I was excited to perform. I was excited to say, "I don't need a harness. Let me do it." And he'd be like, "No, you need one, but I know you can." Things like that excited me as an actor and just like a collaborator. It was really cool and important, and yeah, that was fun for me — really fun to get to use my body like that in this film.
Jeff: I mean, I would go back to your question. You said lean on Kathryn. The only reason I survived this movie is Kathryn. I mean, Kathryn was basically like a flotation device, and I was drowning in the middle of the ocean.
Kathryn: I feel like I knew what Jeff wanted and I just wanted to help him out. Like I wanted to give him what he wanted but a little more, you know?
Five friends set out on one last adventure along Thailand’s stunning coast, eager for a final thrill before life in the real world begins. They sign up for a guided swim through a remote cave system known as The Devil’s Mouth, a natural wonder that's as breathtaking as it is unforgiving.
Deep inside the labyrinth of narrow waterways, their journey takes a terrifying turn when they discover that a freak storm the week before flooded the caves with sea life. The creatures died in the fresh water, but something survived… and it's hunting them now— fast, silent, and deadly. Every corridor they round is overflowing with anxiety, and every wrong turn becomes a deadly encounter.
As panic spreads and their sense of direction slips away, the group begins to fracture. Trust erodes, fear takes over, and survival becomes a savage game. In the suffocating darkness, every choice could be their last as they learn that to make it out alive, sacrifices must be made.
The Devil's Mouth premieres globally on Prime Video on July 29, 2026.