Sgt. Frog Is Back With Every Voice Replaced. The Original Keroro Says It Wasn’t the Actors’ Choice
The new Sgt. Frog TV series premiered in Japan on Saturday with an entirely new voice cast, three months after the original actors starred in a Sgt. Frog film. Kumiko Watanabe, the voice of Keroro for 22 years, has said the change wasn’t the actors’ idea. Fans spent the morning comparing old voices with new ones.
Keroro Gunsō ☆ debuted at 9:30 a.m. on October 3 on TV Tokyo and its affiliates, on a Saturday morning, just as the first Sgt. Frog series did on April 3, 2004. Crunchyroll is streaming it with English subtitles everywhere except Asia, under the title KERORO☆. BN Pictures animates it, with Nobuhiro Kondō as chief director and Akihiko Sano directing.
Every voice is new. Makoto Koichi now plays Sergeant Keroro, the would-be invader from planet Keron who’d rather build model kits than conquer anything. Toshiki Masuda, Rika Nagae, Kōsuke Echigoya and Satoshi Inomata play the rest of the platoon, and the human family that takes Keroro in has new voices as well.
Image: TV Tokyo and the Keroro Gunso production committee (© Mine Yoshizaki, KADOKAWA)
One cast for the film, another for TV
The franchise announced the series on December 23, 2025, and said from the start that it would have a brand-new cast. In the same breath, according to Anime News Network, the staff confirmed that “the existing cast in the franchise thus far will still star in the new 20th anniversary anime film project.”
They did. The film, Shin Gekijōban ☆ Keroro Gunsō, opened on June 26 with Watanabe and the rest of the original platoon back in the booth. So within four months of each other, Japan got a Sgt. Frog film with the old voices and a Sgt. Frog TV series with new ones.
The 20th anniversary film
Original cast back together, led by Kumiko Watanabe as Keroro. Made by staff who worked on the earlier anime.
Keroro Gunsō ☆
A fresh start, from a different director, with every role recast. Makoto Koichi takes over as Keroro.
The official explanation was short. The production called it “a decision made as we create the new Sgt. Frog anime from scratch,” according to Japanese anime site Seichi Map, which reported the wording. No one has said more than that on the record.
“Not what we performers wanted”
Watanabe answered on X the day the recast was announced. “This was not what we performers wanted at all,” the actor wrote. “Pekopon grown-up business? Is that what they call it?” Pekopon is what the show’s frogs call Earth, so the joke lands in character, and so does the point.
Watanabe’s attachment to the role is no secret. In a July 4 interview with Oricon News, given to promote the film, Watanabe described a hard start in 2004. “At first I couldn’t picture my own voice at all. What kind of voice is going to come out for this?” Having fallen for the manga first made it harder: “Because I’d become the number one fan, it turned into a question of whether I could forgive myself for being the voice.”
The goal, Watanabe said, was a performance with a pull to it. “I had to give a performance that’s addictive to listen to.” And once that clicked: “The moment I got there, I felt it. I’ve become Keroro.”
Back in the booth for the film, Watanabe said, nothing felt like a gap. “It felt like we’d just been hanging out a week ago, so for me it wasn’t a reunion. It was a continuation.” There’s a life-size Keroro figure in Watanabe’s front hall at home. “When I say ‘I’m home’ at the door, I do the voice myself,” Watanabe said. The reply comes in Keroro’s trademark military style: “Welcome home!”
The new Keroro speaks first
Koichi didn’t pretend the handover was painless. In a comment published on Bandai Namco Filmworks’ official V-STORAGE site when the cast was revealed, Koichi wrote: “I think many people will feel sad or confused that the cast is changing. I feel that same sadness myself.”
VoiceEditSuiteClean a session in ninety seconds, not three hours.Koichi went on: “As an actor who has been newly entrusted with Keroro, I strongly want to give everything I can right now, without forgetting my respect for everything Sgt. Frog has built up over the years.”
The rest of the new platoon struck the same note. Nagae, the new Tamama, promised to play the part while “carefully carrying all of it forward,” meaning the character’s power, cuteness and jealous streak. Echigoya, the new Kululu, spoke of feeling honoured and also “the weight of that responsibility.”
For working voice actors, the pattern is familiar from the other side too. A long-running role can feel like it belongs to the person who built it, and then a production resets. Sometimes the reason is scheduling, sometimes it’s cost, and sometimes, as here, the public explanation stops at the word “new.”
What fans heard on Saturday morning
Reaction on X was mixed, with a lot of pleasant surprise. Posts collected on Japanese fan site Animin after episode one show viewers listening hard for the old voices inside the new ones.
“Even with everyone’s voices changed, it doesn’t feel off,” one viewer wrote. “You can feel the effort to match the voices from back then. Amazing. I’m so happy.” Another singled out Masuda’s Giroro: “Masuda’s Giroro delivery is amazing too. It’s Nakata through and through,” a nod to Jōji Nakata, the original Giroro.
Not everyone was won over. “Honestly, this is awful,” one viewer posted. “This Keroro just isn’t it.” Others split the difference. Kululu was voiced by Takehito Koyasu in the original series, and one fan wrote that the character “has a very different image now, but this is a new Kululu in its own right.”
Back in December, when the news first broke, Japanese fans had gone through the same argument on X. Some said they understood: “I think this came out of a lot of agonizing, and I want to support it,” one wrote, in posts gathered on Togetter. Others pointed out that, apart from the late Tomoko Kawakami, the original Fuyuki, the old cast were still working and in demand.
The new series airs every Saturday morning on TV Tokyo, with Crunchyroll carrying it outside Asia. The old voices aren’t gone, they’re in the film. On TV, it’s Koichi’s Keroro now.
Viewer reaction to episode one is collected on Animin.
Sources: Anime News Network (premiere and cast, Oct. 3, 2026; announcement, Dec. 23, 2025; cast reveal, Sept. 7, 2026); Seichi Map (official wording and Kumiko Watanabe’s post on X); Oricon News (Kumiko Watanabe interview, July 4, 2026); V-STORAGE, Bandai Namco Filmworks (cast comments); Animin (viewer posts on X, Oct. 3, 2026); Togetter (viewer posts on X, Dec. 2025); Wikipedia (original series cast, episode count). Quotations from Japanese sources are translated by Voice Over Herald. Images: TV Tokyo and the Keroro Gunso production committee (© Mine Yoshizaki, KADOKAWA).
Lee este artículo en español: Keroro vuelve con todas las voces nuevas. Su voz original dice que no fue decisión de los actores
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