At this point in time, I personally doubt it. Jonathan M. Shiff (the producer) announced his new series, Mako: Island of Mysteries, which is a spin-off of H2O, but has an entirely different plot and characters. Unfortunately, the actors and atrizes have grown up a lot (physically) since the show ended, and they're all doing their own productions and roles in different shows and movies. As AMAZING as it would be to have a fourth season, I don't think it's going to happen. If they were planning on a fourth season coming out, they would've announced it por now.over a year ago
i actually found proof there is going to be a season 4 of h2o nickelodeon and jonathan m shiff posted and official season 4 trailer on you tube just type in h2o just add water season 4 official trailer and select the video with the longer time spanover a year ago
Chances are that was fã made. I would think they'd announce it publicly first and only air the trailer once production was near completion or before release date. Sorry! :(over a year ago