Reigisa

Reigisa is the slash ship between Rei Ryugazaki and Nagisa Hazuki from the Free! fandom

Iwatobi Swim Club
Nagisa and Rei first met when Nagisa was trying to recruit members for the swim club. He saw Rei's pole vault and thought that his dive was perfect. Nagisa then started insisting that he join the team, much to Rei's annoyance. However, due to Nagisa's persistence and after seeing Haruka swim, Rei decided he wanted to swim as gracefully as Haruka and agreed to join the sport.

Dive to the Future
Sprouting Dive Start! A Promise on a Shooting Star! Interference of Loss!
 * Rei asks to take another group photo, since he doesn’t look good in it, but Nagisa sends it, much to Rei’s horror.
 * Rei and Nagisa go to Samezuka Academy to tell about Haru’s tournament
 * Nagisa jumps and half hugs Rei in excitement
 * Rei tells Nagisa to that their training camp has to be take seriously once he starts getting over the top ideas

Fanon
Rei and Nagisa are an easy and sweet pair to ship. They have a very close relationship with each other which is often reflected in fanfiction.

They are often shipped because of their opposing personalities with Rei being a perfectionist and a bit uptight and Nagisa being carefree and childish. Nagisa is also very supportive of Rei and vice versa, and both care deeply for each other, not to mention the show often highlights their close relationship with each other specifically.

On AO3 it is the most written ship for both characters, and the third most written ship in the Free! tag.

Quotes
"Where is Nagisa?! I want to see him right this instant!"

- Rei, to Makoto and Haru.

"I'll never allow you to leave."

- Rei to Nagisa, on leaving the swim club.

Fandom
AO3

Tumblr

Trivia

 * Nagisa's animal symbol is a penguin and Rei's is a butterfly.
 * In the fan made abridged series, 50% Off, the two are an official couple.
 * One of Nagisa's reasons for Rei to join the swim team is that Rei has a name that is traditionally for a girl, just like the other three members, and Rin.