Mirage Island (Generation III)

Mirage Island (Japanese: まぼろしじま Phantom Island) is a hard-to-reach location in Hoenn.

In the games
Mirage Island is found on in. However, it can only be visited under highly rare circumstances. The island is inhabited by wild which range from level 5 to level 50. Most notably, the island also bears a tree where the one and only Liechi Berry in the game can be picked. This is the best Berry for Pokéblocks, and will produce Gold Pokéblocks.

Every day, a random number between 0 and 65535 is generated by the game. If this number matches the last two bytes of the personality value of any in the player's party, then Mirage Island will appear. (Consequently, Mirage Island can be made to disappear and reappear for that day by removing and putting back the matching Pokémon in the party, and Mirage Island will disappear at the end of the day barring the unlikely outcome of two matching numbers being generated in a row.) This makes Mirage Island's appearance even rarer than encountering a Shiny Pokémon, although the probability increases with the number of Pokémon the player has. The odds of a single Pokémon activating Mirage Island is 1/65536; this chance is increased to approximately 1/10923 if the player has a full party.

A man in the northeastern hut in Pacifidlog Town will tell the player whether or not he can see Mirage Island, allowing the player to check if they have a matching Pokémon without having to leave the town. Since Mirage Island's number does not change throughout a given day, it is possible for the undefined to freely move Pokémon between the boxes and the party while attempting to check if any Pokémon in the party matches the Mirage Island number.

Technical details
Two random bytes ("Mirage Island bytes") are generated for the day once any button is pressed on the start menu, and will last until the start menu is accessed again past 00:00 (midnight) of the next day. Even though play time has nothing to do with the real-time clock, a game that has reached the maximum time of play (999 hours and 59 minutes) will always generate Mirage Island bytes of 0. Additionally, if a game's internal battery is dead (causing the real-time clock to stop functioning), then new Mirage Island bytes will never be generated, causing the Mirage Island number to permanently stay at whatever value it was before. Currently it has not been precisely documented what happens to a game which has both a dead internal battery and a maximized play time.

In the anime
In Who, What, When, Where, Wynaut?,, , and landed on Mirage Island after Team Rocket's submarine exploded. and Drew were stuck together and both ended up nearly drowning when Drew passed out, before being saved by the resident Wynaut population.

While the island does appear on maps, the whirlpools around it make it almost impossible to get to or from the island.

In the Pokémon Adventures manga
rescues the man searching for Mirage Island on Pacifidlog Island from being washed away from 's storm.

and were washed up on Mirage Island, after meeting up with Juan, Tate and Liza, Juan explains that the time in the island is different from the external world and they were unconscious in the island for twenty-one days. The time on the island does not always travel at a constant speed and when the time on the island goes normal, one can get on or off the island, so Juan carries a -shaped hourglass for this reason. Ruby and Sapphire meet up with and  for the second time and use them to practice Double Battles with Tate and Liza, preparing for the final battle against Kyogre and Groudon.

According to Juan, Mirage Island is not the actual name of the island; rather, this is what people call the island.

Trivia

 * Although include a location pointer for "Mirage Island", any  caught here will simply display "Met on " in their summary. This is because the player is technically still on Route 130's map.
 * Although Mirage Island does not appear in, the route description of Route 130 on the PokéNav Plus alludes to it; "This route was once a big topic of conversation due to a strange island that seemed to appear and then disappear."
 * If a roaming Pokémon goes onto Route 130 while the Mirage Island is present, it can also be found in the tall grass.

In other languages
Wundereiland (Route 130) Isla Espejismo Île Mirage Isola Miraggio マボロシじま 幻之岛