Secret island?

[KantoKid]

im in the bridge over water town and i keep talking to this guy every day and always says mirage island isnt there today or w/e. i heard you need special pokemon to see the island well everyday i change my lineup to see if it works and for about a month ive never been able to get mirage island.

[absol2005]

Uh, pokemons that sense Mirage Island are rare. I think it depends on IVs.

[Suisho Ai]

I heard that if you deposit a Pokemon in the PC the number needed changes. So rather than trying once a day, you can try as many times a day as you want!