Iron Island (Japanese: こうてつじまSteel Island) is an island off the northwestern coast of Sinnoh, which is only accessible by boat from Canalave City.
It was once a prosperous ore mine, but was shut down after the ore reserves dried up. Since then, it was kept open as a training area and habitat for wild Pokémon. Byron, Riley, and the members of the Canalave Gym come here to train, as did Roark in his childhood. Galactic Grunts are also found within the abandoned mine.
The main point of access to Iron Island is at its southern-west corner, which has a dock for access by boat from Canalave City. One of the openings to the inside of the island is blocked by ledges, and thus its role is more like that of an exit. In front of the dock is two sets of stairs, separated by a landing on which a cabin apparently owned by Canalave Gym Leader Byron is located. The stairs lead to another cave opening, the only other way to enter the island.
The cave inside the island is brown in Diamond and Pearl, and black in Platinum. In all three games, the floor of the cave throughout the island is lined with oil drums and I-beams, with the former occasionally serving as obstacles which the player must navigate around in order to access certain parts of the cave sections.
When the player first enters, a pair of stairs facing left and right provide access to the first basement of the island. The left stair leads to a dead-end section, in which a single Camper can be battled. The right stair leads to a larger cave section with several Trainers, where a platform lift at the end can be used to gain access to the second basement of the cave. Once again, there are two sets of stairs facing left and right at the end of the platform lift; this time the right one leads to a dead-end section, where two Workers can be battled. The left stair leads to the largest single cave section of the island, where Riley will partner the player the first time he or she enters it, participating in Tag Battles with his Lucario. Following this point, the remaining Trainers present in the cave are set up in a way such that tag battles against them with Riley as partner are possible, though strictly optional save for the battle with the two Galactic Grunts at the end of the section.
After the battle with the Galactic Grunts, Riley will cease his partnership with the player, and presents him or her with a Riolu Egg as a parting gift; if the player's party is full, he will remain until the player returns with an empty slot in his or her party. The departure of the two Galactic Grunts will also allow the player to access another platform lift that takes him or her down to the third basement. A cave opening in the wall leads to the exit section with another lift, which will take the player straight back to entrance level, where he or she can leave the inside of the island. In Pokémon Platinum, this section also contains the entrance to the Iron Ruins, where Registeel can be battled if the player has a fateful encounterRegigigas in their party.
When entering Iron Island for the first time, Riley will offer to travel through the mine with the player, participating in wild Double Battles with his Lucario. At the end of their travels, he will give the player a RioluEgg, if the player has a space for it in his/her party; if not, he will wait until the player returns with an empty space. Like all stat Trainers, he will fully heal all of a player's Pokémon after each battle.
Iron Island was first mentioned in Shield with a Twist! by Barry as the location he had trained previously and also plans to train again.
Iron Island first appears in Steeling Peace of Mind! as a rocky island populated with many Steel-type Pokémon. Ash and his friends head off on a ferry to the island on Barry's alert, to investigate why Steel-type Pokémon were running amok on the island. They meet Riley and his partner Lucario and find out the cause is due to Team Galactic's machines. The group then discover that Team Galactic are trying to activate the ruins present in the island. In the next episode, Team Galactic continue their plans at the ruins on Iron Island, where they use the Spear Key to scan Mt. Coronet to find the location of the Spear Pillar. Ash and the group succeed in stopping Team Galactic, and Riley and Lucario successively contain detonating bombs placed by Team Galactic which were to destroy the island.
In the manga
Iron Island in Pokémon Diamond and Pearl Adventure!
Iron Island in Pokémon Adventures
In the Pokémon Adventures manga
Byron sent Diamond to train here with Riley, under his supervision due to his lack of training compared to the other SinnohPokédex holders. It was here that Diamond's Tru learned how to attack fast despite lacking in speed.
In the Pokémon Diamond and Pearl Adventure! manga
Hareta went to train at Iron Island after losing to Byron in a Gym battle. He met Riley, who gave him an Egg which soon hatched into a Riolu. After capturing several Pokémon, he drove off a Team Galactic Grunt, at which point his Shinx evolved into Luxio.