Tir Nan Og College is the school for Earth Fairies. Nebula turned her tower into the school. According to the Tome of Magic History, the only solution in locking the Legendarium is in Tir Nan Og. This must mean that Eldora traveled around the world, including Earth, before the Winx returned magic to Earth and freed the Earth fairies.
The college still looks like the palace. But it is revealed that there is an underground chamber where the magic history can be found, which includes the Mythix Wands of the ancestral fairies, who traveled from the Legendarium World to the real world.
The students of Tir Nan Og College wear similar uniforms. They wear green capes that are tied on their chest. The edge of their rosy pink uniform has green lace. They also wear v-cut, pink skirts which has a darker shade of pink at its edge.They also wear sandals that has vine-like laces that are connected from her knees to her shoes.
In "Mythix," the Winx and Eldora go to Tir Nan Og College to find the key to the Legendarium. With the aid of Nebula, Queen of the Earth fairies, and her fairies, mostly of Bloom, they stop the Trix from conquering their school which proved their worth to the Ancestral Wands and earned their Mythix power.