Eight months after winning the documentary Oscar for “Free Solo,” directors Elizabeth Chai Vasarhelyi and Jimmy Chin began working on their next documentary project: National Geographic’s “The Rescue.” The directing duo used never-before-seen footage and exclusive interviews to tell the story of the dramatic 2018 rescue of 12 Thai boys and their soccer coach from a flooded cave. Unlike “Free Solo” and their 2015 docu “Meru,” Vasarhelyi and Chin relied on other people’s footage, Zoom interviews and reenactments to make “The Rescue.” Film screens at the Toronto International Film Festival.

Was “The Rescue” a commissioned project or did you bring the idea to National Geographic?

Vasarhelyi: National Geographic controlled the rights to the footage, and [Jimmy] and I asked if we could direct it. We pursued the project because it was a story we just loved.

“The Rescue” uses never-before-seen footage shot by the Thai Navy Seals. When did you discover that footage existed? 

Vasarhelyi: We had only heard rumors from the divers themselves that they remembered carrying GoPros. When we met in person with the Thai Navy Seals, we were expecting they had at most 90 minutes of cobbled-together material. When we finally came to an agreement with them, we realized there was 87 hours of all of this amazing footage of what happens inside the cave [including] the footage of the kids themselves. It was like looking behind a curtain because we had no idea that was what was involved because we had never seen images of it.

From those 87 hours of cave footage, how did you know what had to make it into the film?

Vasarhelyi: The shot in the movie — what I think of as the Holy Grail shot — is when the children are found and diver John [Volanthen] leads them in a motivational cheer.

“The Rescue” includes several reenactment sequences. You and Jimmy had never film reenactments, so how did you approach it?

In an ideal world, we would have filmed the real participants in the real cave, but as we were unable to get to Thailand because of COVID, we filmed the real divers reenacting certain parts of their accounts from the rescue in a tank in England. Our intention was to try to make them as impressionistic as possible. What it ends up as is a pastiche of real footage from GoPros and reenactment.

The boys who were rescued from the cave were not interviewed for the film. Why did you decide to not include their voices in “The Rescue”?

Vasarhelyi: There is a preexisting deal with another studio who own the rights to the children. We did everything in our power to try and get some access to them, but it didn’t end up working out.

“The Rescue” is your first film after winning the Oscar for “Free Solo.” Is it nerve-wracking to go out with a new film after all the acclaim for “Free Solo”? And do you feel pressure to achieve the same level of success with this film?

Vasarhelyi: Every time we make a new film we feel immense responsibility and pressure, that’s who we are. Mostly because someone has trusted us to share their story with the world, so we have to get it right. Our experience with “Free Solo” was very special, and each film is different. We love “The Rescue” and it’s been incredibly special to spend time with this film during the pandemic.