For a long time, getting another season of Grand Blue felt like wishful thinking.
Season 1 aired in 2018, and fans then spent years waiting for any sign that the anime would return. Season 2 finally premiered in July 2025. A year later, Season 3 arrived in July 2026.
Now Grand Blue Season 4 is already in production.
That is quite a turnaround for an anime that once went almost seven years without a sequel.
Grand Blue Season 4 Is Official
The announcement came on September 22, immediately following the end of Season 3. Alongside the confirmation, the official website revealed a new visual teasing an increasingly heated battle over Iori’s love.
That choice of visual is worth paying attention to. Chisa, Aina and Sakurako have all become increasingly tangled in Iori’s love life, and the manga material coming next pushes that side of the story even further.
For now, though, there is one important detail missing: Season 4 does not have a release date yet. The official announcement only confirms that production has been decided, with more information to come later.
So a 2027 release might look possible from the recent pattern, but it has not been announced.
What Manga Chapters Will Grand Blue Season 4 Cover?
Manga spoilers ahead.
Season 3 ended with Episode 12, “Okinawa Relanding: Behind the Scenes,” showing what Aina and Kouhei were actually doing while Iori and Chisa were together in Okinawa. The episode corresponds to the manga storyline around Chapter 64.
That leaves Chapter 65, “Day Two of Chaos,” as the natural starting point for Season 4.
Chapter 65 is the final main chapter of Volume 16. Volume 17 then begins with Chapter 66, “Sakurako’s Journey.”
That second title should immediately stand out to manga readers.
Sakurako becomes considerably more important from this part of the story, particularly when it comes to Iori. At the same time, the Okinawa trip has already pushed Iori and Chisa’s relationship into territory that is harder to dismiss as the usual cousin-like dynamic.
And Aina certainly hasn’t given up.
In other words, the Season 4 visual isn’t just putting three popular girls around Iori for marketing. The romantic chaos is genuinely becoming a bigger part of the manga.
Of course, this is still Grand Blue. Nobody should expect the drinking, terrible decisions and completely unnecessary nudity to disappear just because the romance is moving forward.
As for where Season 4 will end, that is much harder to call this early. The anime has flexibility in how it arranges manga material, so giving an exact final chapter would be speculation. Chapter 65 is the much safer starting point.
Why Did Fans Have to Wait So Long for Season 2?
This is the strange part of Grand Blue‘s anime history.
The original anime arrived in 2018. Season 2 wasn’t confirmed until years later, and it eventually premiered on July 7, 2025.
There has never been a simple official explanation for why the sequel took that long.
Even director Shinji Takamatsu joked about the situation when Season 2 was announced. He said that after everything they had gotten away with during the first season, he had started wondering whether a second season would ever happen.
One explanation sometimes brought up by fans is the manga’s monthly release schedule, but that doesn’t really account for a gap of this size.
Grand Blue already had plenty of material beyond what Season 1 adapted. In fact, Volume 10 had already been released before the first anime even began airing in 2018.
Production schedules, financing, staff availability and committee decisions can all affect whether an anime continues, but unless someone involved eventually explains the situation, assigning the delay to one specific reason would be guessing.
What we can see clearly is that things changed once the anime finally came back.
Grand Blue Suddenly Has Momentum
Season 2 premiered in July 2025.
Then, immediately after its final episode in September, Season 3 was announced.
Season 3 followed in July 2026, only about a year after Season 2 started airing.
And once Season 3 finished, the next sequel was confirmed again.
That doesn’t officially make Grand Blue an annual anime. There has been no announcement saying a new season will arrive every year.
But the situation is completely different from 2018.
Back then, a season could finish without anyone knowing whether the anime had a future at all. Now the production committee has confirmed the next installment at the end of two consecutive seasons.
For fans, that might be the biggest change of all.
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