Instructions
Understand the odds. Each day, Mirage Island is assigned a random number. If one of the numbers assigned to a Pokemon on your team corresponds to that of Mirage Island, you will be able to visit the island. Mathematically-inclined players have calculated the odds of a match as being less than 1 in 65,000. When Mirage Island does appear, it will be located on Route 130, east of Pacificlog Town.
Speak to the Old Man in the house at the bottom-right of Pacificlog town each day. If he says, "I can't see Mirage Island today," try again tomorrow. This technique is much faster than traveling to the large, empty space of water to check for yourself each day.
When the Old Man finally tells you that he can see the island, immediately travel west past the rocks and sea creatures until you arrive at the beach. On Mirage Island, you will find the rare Liechi Berry and plenty of Wynaut Pokemon.