Regirock, Regice, Registeel
Note : To make the Regi trio appear in their lairs, you must have completed the puzzle in the Sealed Chamber , detailed at the end of the A Final Detour chapter.
The locations of the Regi Pokémon are easy enough to find. You’ve probably passed them by once before! Each is signified by a large rock surrounded by six smaller ones.
Regirock’s lair is on Route 111, in the desert. When in the desert, go far to the southeast and you’ll find it easily enough, it’s virtually impossible to miss. Inside the cavern, face the center of the Braille writing, then read it: "Right, right, down, down.
Then use move Strength." That means walk right twice, then down twice, then use Strength. You’ll have to do so manually from the Pokémon menu, much as you do, for example, Fly. This will let you into where Regirock lies.
Regice’s lair is on Route 105, on the west-northwest side. Again, hard to miss. Inside, the Braille reads "Stop and wait. Wait for time to pass twice." In this case, simply sit the game down and do absolutely nothing for two whole minutes.
And we mean literally nothing: sit the console down away from you and don’t even touch it, hard as that may be. Get a drink or something. Shove down a slice of pizza. Blink. Whatever. Afterwards, the way to Regice will open up.
Registeel’s lair is on Route 120, near the meeting point with Route 121. (You found a Light Ball near it on the Route 120 walkthrough, remember? In fact, the walkthrough blatantly points you to it.) Basically go west of that junction point and upstairs for a bit to find it. W
ithin, the Braille reads "With new time, hope and love, aim to the sky in the middle." In this case, step in the very middle of the room - six steps south of the center of the Braille - and use Fly. You will find that the way to Registeel opens (and your poor bird has rammed smack into the roof).
You already got one of the two during the main story, but you can potentially get the other without trading. However, you’ll need the event-exclusive Eon Ticket item.
For the details, check out the Eon Ticket section towards the very beginning of our guide.