Like other K-pop sensations, Big Ocean sings, raps, dances and attracts swooning fans. But this new group’s meteoric rise is fueled by a skill no other boy band boasts: signing.

The band members — Lee Chan-yeon, 27, Park Hyun-jin, 25, and Kim Ji-seok, 22 — are all deaf or hard of hearing. They use the latest audio technology to help make their music, coordinate their choreography with flashing metronomes and vibrating watches, and incorporate Korean Sign Language into videos and performances.

“Just like divers rely on signs to communicate underwater, we use sign language to convey meaning where sound alone might fall short,” Mr. Lee said. “For us, KSL is not just an element — it’s the heart of our performance.”

The group released their debut single, “Glow,” last year, on Korea’s Day of People with Disabilities, and did their first televised performance incorporating KSL, generating local buzz that reverberated beyond national borders. Soon after, they followed up with “Blow,” a single heavy on English lyrics and American Sign Language.

In September, they were named Billboard’s rookies of the month, and recently they made the Forbes 30 Under 30 Asia Entertainment & Sports List. This month, the band performed at an anime festival in Brazil and at a United Nations tech event in Switzerland, before touring Europe for the second time since spring. Their first American tour starts in late July.

Big Ocean now has 995,000 followers on Instagram and more than 696,000 on TikTok. Fans, who call themselves “Pados” after the Korean word for wave, are devoted, and many are learning sign languages from the band, which makes numerous tutorials.

But fame was never assured, said Haley Cha, the chief executive of Parastar Entertainment, Big Ocean’s management company. “We had many difficulties in developing this band,” she said.

Even the members sometimes questioned their dream, Ms. Cha added. They had alternate careers and it was not always clear to them or to others what they could achieve in music. Mr. Park, who goes by P.J., was a YouTuber, creating content about hearing disabilities. Mr. Lee worked as an audiologist at a hospital. Mr. Kim had been an alpine skier.

Ms. Cha said she used a variety of tactics to help them visualize stardom, including taking images of established K-pop idols and replacing the faces with those of the trio. They have since made videos and performed with industry luminaries.

A Major Breakthrough

Big Ocean’s rise did not happen in a vacuum. The band’s struggles and successes reflect broader advances for South Korea’s Deaf community, nearly a decade after the country recognized KSL as an official language, distinct from spoken Korean.

About a quarter of a million Koreans are deaf or hard of hearing. An estimated 84 percent use sign language as a primary mode of communication and more than a third live in the capital, Seoul.

Historically, there were few educational opportunities for the Deaf community and there was little recognition of Korean Sign Language, said Jeonghwan Kim, the president of the Seoul Association of the Deaf. A national association for the deaf was established in 1946, but the emphasis on education during much of the 20th century was on speech training rather than on signing.

That focus on speech in Korea was part of a wider global trend that was hotly debated, particularly with the development of cochlear implants to aid hearing. Some argue that sign language as an expression of Deaf culture and identity is marginalized when speech is emphasized.

Big Ocean blends singing with signing, and the path for Korea’s embrace of the band was paved with legislation.

In 2016, the Korean Sign Language Act went into effect, recognizing KSL as the official language of the Deaf community. It was “a major breakthrough,” Jeonghwan Kim said, adding that it marked a substantial step forward in securing their “linguistic rights and cultural identity.”

The law led to institutional changes, like the right to request interpreters in public institutions. It also spurred a government KSL program, which continues today.

The National Institute of Korean Language began working to promote KSL and develop educational materials, conducting research on sign language usage, building a dictionary and training instructors, according to Hyesun Chung, a research officer in charge of KSL at the institute. The institute also has tried to promote the idea “that Deaf people have the right to enjoy and express their culture through their own language,” she said.

Those institutional changes have helped shift cultural views, leading to the acceptance of deaf artists, including Big Ocean. The band, in turn, has raised awareness of Deaf culture in Korea and the world.

“Many Deaf youth see their presence onstage as a powerful form of representation,” Jeonghwan Kim said, adding, “Their work broadens the public’s perception of artistic expression beyond sound.”

Global Reach

Big Ocean wanted to make waves worldwide, so the group studied American Sign Language and International Sign to create shows that were more accessible across different cultures. “When fans sign back during concerts, it’s one of the most powerful forms of connection,” Kim Ji-seok said.

Fans do sign back, online and at performances, and the band’s emphasis on signing has helped to educate people about a basic fact: Every sign language is distinct from the corresponding spoken tongue, as well as from other sign languages.

For followers already in the know, the band’s use of sign language is extremely gratifying. Responding to a recent International Sign video tutorial for the song “Sinking,” one commenter with hearing loss wrote, “Been blasting this through my headphones and emotionally signing it all night.”

Another viewer, who teaches English to deaf students in Brazil, thanked the musicians. “You are part of a major change in the world,” the instructor wrote.

Liam O’Dell, a deaf author and journalist, said Big Ocean deserved credit not just for their catchy songs and for incorporating sign languages into music videos but also for debunking what he called the “frustrating misconception that Deaf and hard-of-hearing people can’t make or enjoy music.”

The band is open about its creative process and has brought attention to a different sensory experience of music beyond sound, including through lights and vibrations. Members have shared their techniques for coordinating dance routines with buzzes and flashes, and they candidly discuss using artificial intelligence tools and other technology to perfect singing pitch.

Amid all the good fortune and positive vibes, however, there is an undercurrent of tension. Some in the Deaf community worry about the framing of the band, particularly for hearing audiences, as an inspirational narrative about “overcoming” disability that could undermine Deaf identity. They also worry about signing being deployed decoratively rather than as an expression of a culture.

“While Big Ocean’s presence has opened doors, it’s vital that their work — and the culture it represents — be shaped through Deaf perspectives, not merely filtered through a hearing gaze,” Jeonghwan Kim said.

For their part, the trio’s members seem delighted that they inspire people and heartened by the world’s response. “Knowing that our music resonates with Pados worldwide motivates us to keep pushing boundaries,” Mr. Park said, using the name for the band’s fans.

Mr. Lee noted that at a recent meeting, they met fans “who were overcoming cancer, surviving school bullying or healing from personal hardships” and who felt inspired by their work. “One fan told us, ‘You’re proof that something that seems impossible can actually happen,’” he said. “That moment really stayed with me.”

Jin Yu Young contributed reporting.