CASTLE SWIMMER drops final season release date

Say it ain’t so! Do we really have to say goodbye to our favorite merboys?

Creator Wendy Lian Martin announced that fourth and final season of the fantasy webtoon series Castle Swimmer will launch on July 13 on WEBTOON. Season 4 will begin after almost a year since the conclusion of Season 3 on July 27, 2024. Castle Swimmer is hugely popular, amassing more than 340 million views.

Castle Swimmer follows two boys whose fates are closely intertwined. Kappa is a Beacon, the guiding light for his people; Siren, the shark prince, is destined to kill the Beacon so his people may survive. When the two meet, they fall head-over-tail in love with each other. Although it seems as though one will survive and the other will die, the two are determined to change their destinies–together.

Have no fear, though, readers. Martin is already working on another series, and is currently brainstorming it, which you can read on WEBTOON. Bird Boy is another fantasy romance tale but according to a recent update in March 2025, the concept of the story as it currently stands in Bird Boy may be very different by the time it gets published sometime in 2026.

Comics Beat sat down for an interview with Martin back in October 2024 to celebrate the release of the print version of Castle Swimmer Vol. 1, published by Ten Speed Graphic, and asked what readers can look forward to in Season 4.

“It’s every big thing that I’ve been preparing for and building up towards in the other seasons,” Martin said. “When I look at this season, this is a crazy season with all of this stuff that’s been happening. There have been some big moments in the past seasons but by comparison, it just kind of feels like they’ve been hanging out. […] I’m pretty confident that the readers are going to really enjoy it.”

Castle Swimmer will be swimming to its final season on July 13. Catch it on WEBTOON. The first volume of the print edition is out with Vol. 2 coming on June 3.

Source: X, formerly known as Twitter