I think it depends on what day you enter it. When it appears is completely random. Kinda like Mirage Island, only more common.
When can Mirage Island appear?
~ Only after beating the E4?
~ Only after catching rayquaza?
And, Can it come back / how long is it there?
I have Pokemon Emerald and I am unable to find the Mirage tower. First of all, it is in the desert by route 111 right? I walk around as instructed in walkthroughs and don't have any luck finding it. I tried walking out of route 111 and back, and still no mirage tower. Do I have to step on one specific tile in the entire desert, thus making it difficult to find, or does it just kind of show up as im walking around? (i dont think that made any sense but it does in my head)
For me, Mirage tower appered as soon as I walked into route 111 as soon as I got the go-goggles. (I ran over to route 111 after beating Flannery, then it appeared!) Was that luck, or was it supposed to happen?
Soul Silver: FC: 1033-7425-8991 Name: Andrew
Black: FC: 5028 3780 4610 Name: Hammy