|Season 1, Episode 4|
|Air date||July 25, 2013|
|Written by||Masahiro Yokotani|
|Directed by||Hiroko Utsumi|
|Theoretical Dolphin Kick!||Trial in Open Water!|
The Swim Club officially starts training in the refurbished pool using an old training regiment of Rin's Gō had unearthed. Rei's inherent academic skills at learning all the swimming theory prove to be useless since his body refuses to move in the water. Elsewhere, Rin grudgingly realizes that his victory against Haruka was due to Haruka's lack of physical training and not his actual talent. Nagisa and Makoto start teaching Rei how to swim and learn that while he can float, his problem still eludes them. The following day, the guys try to come up with designs for a club uniform but Gō instead gives Rei's lessons higher priority and makes a revamped swimming regiment during which he must master swimming in one week before their first prefectural tournament. Nagisa and Makoto try and fail to teach Rei their signature techniques; the breaststroke and backstroke respectively causing Rei to blame his inability on their teaching methods. Makoto suggests they ask Sasabe for help but he bluntly refuses. During the weekend, Rei attributes his inability to not having proper gear, hence prompting a visit by the team to a sports store to buy swimming essentials. At the store, Haruka and Rin run into each other and have a short discussion about their differing forms with Rin wanting a race with them both in peak condition, or else he may no be able to move forward from his loss and both decide to settle the score at the upcoming tournament. Afterwards, Haruka takes a turn trying to teach Rei freestyleswimming and fails, greatly disappointing Rei. As the day draws to a close, Haruka laments to Rei that he too isn't compatible with other techniques in that he doesn't swim freestyle by choice; merely because it is all he can swim. The next day, having come to this realization, Rei tries the last technique and finds it compatible with himself: the butterfly stroke.