|“||Augh~ I'm itching to get started! Hurry up and produce me, Producer!||”|
|— Umi Kousaka, Online Character Profile|
A hyperactive girl among the idols, Umi is an athletic girl who excels at almost every sport, and most of her cards depict her doing various sports. She has a very energetic personality to the point that she cannot stand being inactive. Umi can’t calm down when she's not doing anything-- in fact, she once said that when she remembers that there are other idols out there who are working their hardest, her body is unable to rest.
Umi is not only good with active sports like football or basketball; she is also good with gymnastics, and she took ballet lessons when she was younger. All of this made her body very flexible. While she is a sporty girl, she's definitely not a tomboy and she's happy to wear cute dresses. While Umi has great confidence in her legs, she lacks confidence in the upper half of her body and she's not good with makeup.
- Umi is a terrible cook. She once tried to make a Christmas cake and it ending up being elastic like a Gummi candy, making it inedible.
- Umi calls her fellow idols by nicknames, such as calling Yuriko Nanao "Yuririn" as in the Beach Volleyball event and calling Sayoko Takayama "Sayochin" in her caravan story.
- She is nicknamed “Umimi” by fans because her name’s kanjis (海美) can be read as such. She even used it herself in some of her card’s text and event dialogues.