From Bulbapedia, the community-driven Pokémon encyclopedia.
Dandelion Island (Japanese: タンポポ島 Tanpopo Island) is an anime-exclusive location in Sinnoh, which is nearby Lily of the Valley Island. It was featured in Bucking the Treasure Trend!.
The island is covered with mountainous and forest terrain. Dandelion Island is most often visited as a restock point for ships in the town on the southern coast of the island. People who actually venture onto the interior of the island to explore are viable to run into Pokémon set as traps such as Voltorb, Pineco, Vileplume, and Graveler, along with Gloom and Golem that don't appear on the island's treasure maps. These Pokémon guard a set of ruins, wherein lies a Claydol guarding some ancient pottery.
When Ash's friends, en route to the Lily of the Valley Island, along with Buck, arrive at these ruins, Team Rocket sets off the trap, triggering the Claydol's emergence. Buck later captures this Claydol and discovers the ancient pottery it was guarding.
Pokémon seen on Dandelion Island
|| タンポポ島 Tanpopo Island
|| From タンポポ dandelion.
|| Dandelion Island
|| From dandelion.
| Chinese (Taiwan)
|| 蒲公英島 Púgōngyīng Dǎo
|| From 蒲公英 púgōngyīng, dandelion.