Yardrat is the planet the Ginyu Force were scheduled to invade before being relocated to Namek. After Goku could not start Frieza's spaceship, he finds the Ginyu Force's ships nearby and takes one of them. The coordinates for Yardrat were already programmed on the ship's computer, and thus it goes to this planet with Goku inside.
While on the planet, the Yardrats nurse Goku back to good health and even gave him the same outfit that the Yardrats wear replacing his outfit as it is all torn up after his fight with Frieza. Soon afterwards, he is taught the Instant Transmission technique by them. Goku stays on the planet for about a year before heading back to Earth. In Dragon Ball Super, Vegeta after a reluctant retreat from the deteriorating New Namek, forces Irico to fly to Yardrat so he could learn something to help defeat Moro under the guidance of the Yardrat elder, Pybara who was responsible for teaching Instant Transmission to Goku during his stay on the planet.
During his training, Vegeta learns the art of Spirit Control which is what allows the Yardrat to perform techniques such as Instant Transmission, Cloning, and Gigantification. However one of the most difficult abilities granted by Spirit Control is Forced Spirit Fission, a technique too complex for even Goku to master. However Vegeta manages to learn Forced Spirit Fission during his stay giving him a powerful tool in the fight against the Moro Corps. It is also revealed that under normal circumstances, Yardrat are forbidden from teleporting off-world. However Elder Pybara was willing to make an exception and teleport Vegeta to Earth, but Vegeta refused, instead developing the ability to utilize Instant Transmission which eventually utilizing it to make his way back home to Earth to join the fight against Moro.
Video Game Appearances
In Dragon Ball Online, according to the game's timeline Planet Yardrat is destroyed sometime before Age 900 by the Demonic Bio-Android Mira forcing the surviving Yardrat refugees to relocate to Earth, where the Namekians had previously fled to after New Namek was destroyed in Age 851 by Mira using a Spirit Bomb made of energy from the Dark Demon Realm Army.
In Dragon Ball Z: Kakarot, Planet Yardrat is mentioned by Goku after he returns to Earth and Goku wears his Yardrat clothing until he returns home to convince Chi-Chi to let Gohan train with him and Piccolo to confront the Androids. After Piccolo helps the Alien couple and their travel guide the ex-Combatant Melone in the Sub Story: "Close Encounters of the Troublesome Kind", Melone decided their next stop will be Planet Yardrat to try some of the local sweet potatoes.
- Melone: "Yeah, yeah. I guess we could stop by Planet Yardrat and try their sweet potatoes..."