Icelyn Lee

Icelyn Lee is a supporting character and close friend of Soo Lee. She suspects that something secret is between Choa and Soo, believing that they are ‘secretly dating’.

Appearance
Icelyn has short black hair that is always tied into a ponytail and light brown eyes. She also has bangs.

Icelyn is usually wearing her school uniform, which consists of a short, black, pleated skirt, and a white collared shirt with a beige sweater on top. However, she usually never wears the black ribbon around her collar even though it's a part of the standard uniform.

Personality
Icelyn is a somewhat stoic person who shows her livelier sides to her friends. She cares quite a bit about them and is extremely loyal to them, to where Chan Song has even said before that she's "too faithful" for refusing to watch a movie with him when Soo wasn't able to go watch it with them. Icelyn also seems to have a lot of curiosity and has a habit of jumping to conclusions quickly, especially about Soo and Choa's relationship.

History
Icelyn has been close friends with Soo Lee and Chan Song since childhood.

Episode 1
Icelyn attends the swim meet that Soo is swimming at with Chan Song. Later, Soo tells the two that he saw Choa Shin attend as well. Icelyn and Chan betted on whether she was there, resulting in Icelyn losing

Soo Lee
Soo and Icelyn are close friends. Icelyn seems to care about him a lot. She quickly suspected that he and Choa Shin are dating. She now knows that he is teaching Choa how to swim.

Chan Song
Chan and Icelyn are close friends.

Choa Shin
Icelyn was rather suspicious of Choa and suspected that she and Soo were dating. She now knows she is a mermaid, and promises to keep that fact a secret. Icelyn would now assist Choa whenever she needed it, and apologized to her for her actions and thoughts prior to when she thought she was a mermaid. Though, she struggled thinking of ways to apologize to her, and some of their interactions were still awkward.

Swimming Lessons For Mermaid in 2020 | Anime, Webtoon, Swim lessons
Icelyn and Harim are classmates. They don't seem particularly close but are comfortable enough with each other to ask each other random questions.