What would you like to edit?


Alternative Titles

Japanese: イオ


Type: Manga
Volumes: 10
Chapters: 55
Status: Finished
Published: Aug 19, 1999 to Oct 15, 2004
Genres: Drama Drama, Mystery Mystery, Romance Romance, Supernatural Supernatural, Ecchi Ecchi
Theme: Harem Harem
Demographic: Seinen Seinen
Authors: Koio, Minato (Story & Art)


Score: 7.341 (scored by 22202,220 users)
1 indicates a weighted score.
Ranked: #42652
2 based on the top manga page. Please note that 'R18+' titles are excluded.
Popularity: #3348
Members: 6,257
Favorites: 58
Ranked #4265Popularity #3348Members 6,257
Add to My List
Volumes: /10
Chapters: /55


Taiyo Nakabiru went to Okinawa on a trip in pursuit of beautiful girls and his wish to go diving. When trying to hit upon a girl, she surprises him by saying that he killed her mother. It appears that she and her two sisters know him, even though he does not remember ever going to Okinawa before. After convincing the three sisters, Nagisa, Shibuki and Mio Miyara, to let him help them out with their work and to let him learn diving from them, Taiyo's childhood with the sisters slowly comes back to him, and certain strange events involving a mystical white whale begins to haunt them.

(Source: ANN)



Oct 23, 2007
IO basically starts of as a distinctive Harem, Romantic, Comedy, but as you go on you’ll discover that there is more to this manga, once the Supernatural, Mystery element surfaces.

It follows the endeavours of your average city boy (Taiyo), who visits Okinawa, only to end up meeting 3 girls. It appears that he once was acquainted with the sisters, some time in the past, yet he can't seem to recall any of it. That’s basically how it all begins and behind what would seem like a typical Rom/Com lies a fantastic story of supernatural mystery, scuba diving and ancient relics. The way in which the ...
Aug 11, 2008
This was one of the most unique stories that I've had the privileged of witnessing in a long time. This was a cross between harem, mystery, Romance, and sport (if you consider scuba diving a sport that is).
The story starts out with a class trip down to some tropical islands where our lead protagonist meets a girl who blames him for killing her mom. One thing leads to another and the next thing he knows he's learning how to scuba dive with some long lost, and apparently forgotten friends. Now this story really has two stages to it. It ...
Dec 29, 2015
Gosh, it must have been while I was in college that I read this manga. Now several years later, with a bit of time to spare, I saw it pop up again in my browser history (yeah, yeah, I really need to clean it up one of these days) and couldn't stop myself from diving right into it (you see what I did there? *wink* *wink*).

I can tell you one thing: it was a mistake. A horrible mistake.

No, not because it was terrible. I fell in love with it once more (as far as that's possible with something on paper/your computer screen) and couldn't help ...

Interest Stacks


Recent News

Recent Forum Discussion

is this a comedy like granblue?
Neostorm-X - Jul 14, 2023
0 repliesby Neostorm-X »»
Jul 14, 2023 6:26 PM
Poll: IO Chapter 55 Discussion
Laevantein - Nov 8, 2009
18 repliesby Farabeuf »»
Jun 30, 2020 1:47 PM
Poll: IO Chapter 54 Discussion
Laevantein - Nov 8, 2009
2 repliesby Farabeuf »»
Jun 29, 2020 1:37 PM
Poll: IO Chapter 50 Discussion
Laevantein - Nov 8, 2009
1 repliesby Farabeuf »»
Jun 28, 2020 1:38 AM
Poll: IO Chapter 49 Discussion
Laevantein - Nov 8, 2009
1 repliesby Farabeuf »»
Jun 27, 2020 5:06 AM