If Tina Landau hadn’t become a director, she probably would have followed in the webbed footsteps of Jacques Cousteau.

“When I was a kid, I wanted to be a director or an oceanographer,” says Landau. “I was always attracted to the idea of being underwater.”

Now she gets to embrace her love of all things aquatic as the woman at the helm of “SpongeBob SquarePants,” the musical based on the smash Nickelodeon cartoon about everyone’s favorite happy-as-a clam sponge that opened Monday at the Palace Theatre on Broadway. “We’ve tried to create an environment from the moment you enter where … the feel of the place takes you underwater in this completely idiosyncratic and colorful environment,” says Landau. “We use the aisles to a great extent and we have a passerelle built into the house where the action takes place.”

SpongeBob’s hometown has been recreated in all its watercolor splendor from the pineapple he calls home to the backgrounds of ocean fauna and umbrellas that resemble jellyfish. It’s the culmination of a voyage to the bottom of the theatrical sea that’s been 10 years in the making, starting from the moment Landau’s agent asked her to meet with Nickelodeon. Her initial reaction was to say no.

“I assumed that what Nickelodeon wanted to do was a stadium show with a big mascot and foam costumes,” Landau says. “They said they only wanted to do this if there was a way of making it new and inventive and to bring new life to the brand. That was very freeing to me.”

It took a year following that initial meeting before Landau was hired. Her first assignment was holding a workshop to discuss her vision for the physicality of the show with the producers. Landau insisted the actors not be in full body costumes, but wear the simplest of wardrobes to enable them to be use their bodies freely. That was especially necessary for Ethan Slater, who plays the title role and is often required to contort his body in unimaginable ways.

“I have splits where I’m bending myself in half. I’m singing upside down," says Slater, whose costume consists of a button-down shirt, red tie and those famous pants. “Each time I’ve done the show, I’ve learned a special skill or a new little trick I never thought I would be doing. I’ve trained myself to be more flexible.”

Next came the search for a book writer and a second workshop devoted to creating the story. The premise of Kyle Jarrow’s book is that SpongeBob, his dimwitted starfish buddy Patrick and squirrel gal pal Sandy must prevent a volcano from destroying Bikini Bottom. Along the way, the show deals with themes of community, adversity and loving thy neighbor.

Tying the story together is an eclectic array of songs ranging from heavy metal to gospel penned by an impressive roster of artists, including John Legend, David Bowie, Sara Bareilles, Steven Tyler, Joe Perry, Cyndi Lauper and Panic at the Disco!

Also in the mix are the TV show’s theme song, and “Best Day Ever,” which was written for the series by Andy Paley and Tom Kenny, who has been the voice of SpongeBob since the first episode in 1999.

“I had nothing to do with that getting in the Broadway show,” Kenny says. “I was jazzed about it. When I saw the show in Chicago, it was ingeniously used as the 11 o’clock song where things look their worst and destruction of everything seems imminent … We wrote it as this anthemic thing. We needed a song that’s summed up SpongeBob’s philosophy toward life.”

It wasn’t until 2012 that Landau began to cast the show then labeled “The Untitled Tina Landau Project.” Slater was on summer break from Vassar College and appearing in Connecticut in “Romeo and Juliet.” The casting director for that show recommended that he try out for “SpongeBob.”

Landau was captivated immediately. “SpongeBob is just about exploring the ability to see the world with childlike eyes full of wonder and a very particular humor, which Ethan has,” she says. “He really knew the show. He just shares a sensibility with that little yellow sponge.”

Both Slater and Danny Skinner, who plays Patrick, spent hours watching films of classic slapstick comedians, including Charlie Chaplin, Harold Lloyd, and Laurel and Hardy to prepare for the show’s demanding physical comedy. At the same time, the actors aren’t trying to just do an impersonation, least of all their cartoon inspirations.

“We are real people, so we can’t possibly be cartoon characters,” says Skinner. “The costumes are an extension of that. I get a little bit of a tie dye and six Hawaiian shirts and a pompadour and it is so distinctly Patrick without just being an imitation of the television show.”

For Slater, one of the hardest facets of his character was mastering that distinctive high-pitched SpongeBob laugh. “When I auditioned, I didn’t even try to do the laugh, not because I was being clever, but because I was so confident I couldn’t do it,” Slater says.

Not only has he got the laugh down, but it earned the seal of approval from Kenny, who attended the show’s Chicago opening in June 2016 and has a voice-over role in the Broadway show as the French narrator. “Tom Kenny is awesome,” Slater says. “We talked a lot at the opening night party. When we went to L.A. in the fall, the whole SpongeBob team met me at the Nickelodeon building and Tom Kenny was there and we had a laugh-off. He laughed, then I laughed, then we laughed together and that felt like a pretty good pat-on-the-back endorsement.”

Since the Chicago tryout, “SpongeBob” had some retooling and Landau has been happy with the changes. “We looked at every moment, every character, every song and asked how can this be better,” Landau says. “We deepened characters and their relationships with each other. We have given the story even greater resonance to the world we live in.”

Tied to that, Landau hopes that the end result will be that audiences soak up some of that SpongeBob optimism. “A year and a half before Chicago, I said the world needs a SpongeBob musical. I was both cheered and jeered for that statement,” she says. “I stand by it even more strongly today. I think it’s less about escape from what’s going on in our world and more about telling a story that echoes and reflects our world, yet reminds us how important it is to treasure each other, treasure our community, treasure diversity, and most of all embrace joy in how we live each day that we’re granted.”