Cularin is one of the ocean worlds in the Cularin system. Along with Acilaris, it shares an orbit that is very close to the system's suns, producing extremely hot summers and warm winters. The lack of a cold season makes this planet very viable for plant and crop growth.

The surface of Cularin is mostly covered by vast oceans, which are full of aquatic life. Deep swamps, dense forests, jungles, and a large glacier region can all be found on this diverse planet. The planet's warm temperate climate led to a large diversity of wildlife to evolve across the surface. The large variety of land-based predators that live on Cularin makes traveling in the dense jungles an extremely dangerous venture. The planet has two moons - the molten Rennokk and the barren Tilnes, which is known throughout the region for its exotic hardwoods, especially the ch'hala tree.

Cularin has one large landmass in the western hemisphere, mainly consisting of a massive metropolis. The cities are home to many sentient beings, most of which are displaced Nautolans who fled their nearby homeworld of Glee Anselm many years ago to get away from the war-plagued planet. The immigrants, led by the Nautolan Society, claimed the planet as a new homeworld for their race, free from the oppression found on Glee Anselm, and began construction on their grand city. The city grew very fast and soon covered a large section of the landmass of Cularin. The planet's population is steadily on the rise, making it a popular place for immigration and development.

After the Confederacy was defeated in the Battle for Dolomar, most of the first fleet settled in the Cularin system. Some Old Republic forces followed the damaged Confederate ships to the system and a large-scale water battle took place on Cularin between the Separatists and the Republic forces. While the result of that battle is unknown, the bottom of the Cularin oceans are littered with the remains of not only wrecked ships but also of the starfighters that were destroyed high above in the plant's atmosphere during the battle.