Obsidia Island is a hot and fiery isle on the vast ocean out of range for the Roria Map. It houses a crimson, seemingly-active volcano named Obsidia Cavern. Despite that an active volcano is on this island, the shoreline is beach-like with some Arecaceae trees growing. The Wild Pokémon here prefer to stay inside the cave and thus are not found on the exterior.
There are scarcely any travellers who have set foot on this island. A side quest is required to be completed in Decca Travel Agency, Port Decca before players can get the Obsidian Ticket for reaching this isle.
Obsidia Cavern Entrance
A big hole on the base of that crimson volcano leads to Obsidia Cavern, which can be considered as a smaller version of Mt. Igneus. It is seen right in front of the player once he or she sets foot on this island. A few species of Fire-type Pokémon, with some of them being familiar and the remaining one being a new face, live inside the volcano along with a Legendary Pokémon.
- Obsidia Island is possibly a reference to Faldera Island, Oblivia in Pokémon Ranger: Guardian Signs. Both are active volcanoes on offshore islands and are home to the same Legendary Pokémon in their summit craters.
- Players can neither surf nor fish on this island, despite being surrounded by the sea. This same case occurs on Voltridia and Frigidia Islands.