The Devil's Mouth: Cast and Director on Filming a Thai Shark Thriller

A Survival Thriller Born in Thai Waters

Something about caves stirs the imagination — dark, ancient, and unyielding, they are places where light struggles to reach and the unknown waits. Thailand holds thousands of them, from the limestone cathedrals of Krabi to the forested mountains of Mae Hong Son. Now a new survival thriller turns that natural wonder into screen suspense.

The Devil's Mouth (ปากปีศาจ), streaming now on Prime Video, follows five young adventurers drawn to Thailand's breathtaking coastline. Their expedition leads them to a remote cave known as The Devil's Mouth, where they join a cave-diving tour. What begins as an adventure becomes a desperate struggle when something begins stalking them beneath the water. Swift. Silent. Deadly.

Shot entirely in Thailand — in Bangkok, Krabi, Mae Hong Son, and Samut Prakan — the film stars Kathryn Newton, Lana Condor, Gavin Casalegno, Nico Hiraga, and Tommi Rose, alongside Thai actor Tayme Thapthimthong, whose performance in The White Lotus Season 3 caught the attention of director Jeff Wadlow (Kick-Ass 2, Never Back Down). This week, the cast and director shared behind-the-scenes stories with Khaosod English in an exclusive interview compiled by Benjarong Kotchanawong.

Tayme Thapthimthong: A Homecoming Role

For Tayme Thapthimthong, The Devil's Mouth was more than a job — it was a homecoming. A Thai actor who grew up watching Jeff Wadlow's films, Tayme had just wrapped The White Lotus Season 3 when the director reached out. It was the first role of his career offered without an audition.

"Jeff later told me that he had seen my performance in The White Lotus and liked my work, which is why he reached out and offered me the role directly," Tayme told Khaosod English. "I'd been a fan of his films for years, especially Kick-Ass 2 and Never Back Down, which I loved growing up. So when I found out I'd be working with him, I was thrilled."

In the film, Tayme plays a cave-diving tour guide who leads a group of international tourists into The Devil's Mouth. Wadlow wanted the performance to feel as natural as possible. "My character is a local guide who knows the cave inside and out. At first, he doesn't suspect that anything is wrong. But once disaster strikes, his only goal becomes getting every member of the group out alive."

The Thailand shoot sealed the decision. "It gave me the chance to come home and spend time with my family." Working with Wadlow, he added, was smooth from beginning to end — and the two remain good friends, keeping in touch regularly.

A Month in the Pool, Then Into Real Caves

About a month before principal photography, all six main cast members gathered in a two-meter-deep swimming pool. Professional diving instructors trained them in freediving — holding the breath without oxygen tanks — as well as scuba basics.

"We trained in the pool almost every day for nearly a month, and practiced breath-holding because many scenes required us to stay underwater for extended periods," Tayme recalled. "It was a fun experience, and it also helped all of us become much closer before production officially started."

The first location was a cave entrance in Mae Hong Son, where the crew shot a canoe sequence, before moving to a cave in Krabi. Filming in real water brought genuine challenges: the cave water was cold and murky, filled with branches and leaves. Professional divers inspected every site before filming, but the tension was unmistakable.

In one scene, the actors jumped into water about 30 meters deep. "Naturally, everyone was a little nervous," Tayme admitted. Between takes, he floated alone in the middle of the water, imagining whether a fish — or something else — might suddenly appear beneath him. (Laughs.)

Another cave was nearly 70 meters deep and profoundly dark. During one scene, an actor accidentally kicked a colleague with a diving fin, startling everyone. "Looking back, though, it's something we can all laugh about now."

After the real caves, production moved to a studio in Bangkok, where the design team built two full-scale cave sets. One was a five-meter-deep underwater cave built for submerged scenes; the other held water about 1.6 meters deep, so actors could stand comfortably during dialogue instead of treading water. The set was designed like a maze, with interconnected swimming chambers — a tribute to Thai production craftsmanship.

3,000 Curves, Motion Sickness, and 4 A.M. Sunrises

For Tayme, the hardest part of the shoot was not the diving. It was getting to Mae Hong Son.

"We had to drive through more than 3,000 winding mountain curves to reach the location," he said. Many international cast members had only just arrived in Thailand, unaccustomed to the climate and the relentless mountain roads. The crew asked Tayme to help look after them — and he became a real-life tour guide.

"I handed out motion sickness medicine, asked the driver to stop whenever someone needed a restroom break, and helped everyone get through the trip as comfortably as possible." Stopping wasn't always possible, he added, because the narrow mountain road would be blocked for the vehicles behind. "Looking back now, it was quite a chaotic experience — but also a funny one."

The entire production made the journey — makeup teams, equipment trucks, even crane operators. And every morning, the crew rose at 4:00 a.m. to capture the first light of sunrise.

Still, the experience was warm. In Krabi, the cast stayed at a beachfront hotel, sharing dinners, swimming, and watching sunsets over cocktails after filming. Tayme introduced his colleagues to local restaurants in Ao Nang, authentic Thai cuisine, and the daily lives of local people. "Those moments remain some of my favorite memories from the entire production."

Pad Kra Pao, Peanut Allergies, and a Love Affair With Thailand

Director Jeff Wadlow had long dreamed of making a shark movie. "I think almost every filmmaker dreams of making a shark movie at least once in their career. Shark films have become a genre all their own." But he wanted something fresh — a film that was both a shark thriller and a claustrophobic survival horror story. The script delivered, particularly in the relationships between its female characters, which he called "the emotional heart of the story."

His enthusiasm for Thailand, however, arrived with a challenge. Wadlow is severely allergic to peanuts. The film was originally set in Mexico; when the studio proposed moving production to Thailand, his first reaction was hesitation. "I'd never even dared to eat at a Thai restaurant before because I was always worried about accidentally eating peanuts."

The Thai production team answered with reassurance: "Don't worry. We'll take good care of you. Everything will be fine." They kept their word. Wadlow learned to avoid Massaman curry and Pad Thai, and discovered a steady favorite — Pad Kra Pao. "I could honestly eat it every single day and never get tired of it."

Scouting locations near Chiang Mai and in Krabi, he stopped at countless roadside restaurants. "Every meal was flavorful, authentic, and packed with character, and every restaurant owner welcomed us with incredible warmth and hospitality." He has since returned to Thailand on his own time, just to visit friends made during production, and hopes to shoot another film in the country.

Survival, Not Combat: A New Kind of Action

Casting, for Wadlow, came down to finding genuinely interesting people. He found them in Kathryn Newton, Lana Condor, Gavin Casalegno, Nico Hiraga, and Tommi Rose. Newton, best known for romantic comedies, welcomed the physical challenge. "This film was unlike anything I'd done before. Most of my previous action projects revolved around fight choreography, but The Devil's Mouth isn't about fighting — it's about survival. The challenge wasn't defeating an enemy; it was simply staying alive."

Even between takes, the cast could not relax. "While the crew was resetting cameras or preparing for the next take, we had to keep swimming or tread water continuously so we wouldn't sink." The result, she said, is an action thriller delivered through endurance rather than combat.

Newton also praised the bonds formed on set. "We went through diving training together before filming began, we built trust and formed genuine friendships long before the cameras started rolling. We became like a little family."

Wadlow sums up The Devil's Mouth in three words: Thrilling. Emotional. Water. At its heart, he says, it is a story about friendship, courage, resilience, and the instinct to survive against overwhelming odds. It is also a cautionary tale about nature's power.

"Nature is breathtakingly beautiful, and that's precisely what makes it so powerful and awe-inspiring. At the same time, nature can also be incredibly dangerous. Our role isn't to conquer nature or believe we can control it. Our role is to admire it, respect it, and recognize its power."

That message resonates with particular force in Thailand, a Buddhist kingdom where the monsoon, the sea, and the forest have long commanded humility from those who live alongside them.

Thailand's Growing Soft Power

For Thai and Southeast Asian audiences, The Devil's Mouth carries significance beyond entertainment. It is a marker of how far Thailand's film industry has come.

Wadlow was unequivocal about the Thai crew. "They were among the most dedicated, hardworking, and resilient professionals I've ever had the privilege of working with." The production's footprint stretched across the country — from the studio sets of Bangkok to the caves of Krabi and the mountain roads of Mae Hong Son — creating jobs, building skills, and showcasing Thai locations to a global streaming audience.

The film also reinforces Thailand's soft power. When Prime Video viewers watch limestone cliffs rise from turquoise water, glimpse the roadside meals of Chiang Mai, or witness the warmth of Thai hospitality through the cast's eyes, they are seeing the Thailand that the country's tourism and cultural ambassadors have long promoted.

As Lana Condor put it: "I absolutely fell in love with Thailand. The country is stunningly beautiful, the food is incredible, and the people are some of the warmest and kindest I've ever met."

The Devil's Mouth is now streaming exclusively on Prime Video.

By Ann Srisawat, Staff Writer

This article was produced with AI-assisted research and editorial support. Reporting is based on sources cited in the article.