You have to have pokemon ruby Sapphire or emerald if you do have one of them here's how you get them
BEAT THE ELITE 4....you must have a Wailord (evolves from Wailmer lv. 40) and a Relicanth(they can be caught in the grass below Sootopolis although you have to be really patient). I recommend to fish with a Super Rod anywhere, and you will find a Wailmer.
Then you will have to have a pokemon that knows dive, and Dig. Fly to Pacificlog, and surf into the rapids. Try to stay to the bottom until you come to completly open land. Then stay in the middle. When you come to the little patch of deep water you will dive and be in a cavern full of rocks with dots (braille) on it. Then surf south underwater until you hit some braille. Use dive there and you will be in a cavern full of braille. Go to the middle braille and use dig. You will then be in another cavern then use dig on the middle braile again. Then it will say, "it sounded like a door opened up far away."
Regirock: Fly do Dewford then surf Northwest until you hit a patch of land with a hiker on it and some trees. Go to the very left of that island, and surf straight up. There will be a cave. Look at the middle braille and wait after 3 mins the door will open.
Registeel:Fly to Lilycove and go west until you find a lady who will give you a berry. Go to the planting place and you will find a mudslide thing go up it with your mach bike and you will find a hiker and a huge rock, go inside and read the braille, then go to the middle of the cave and use fly.The door will open.
Regice:Fly to Lavaridge then go to the mauville desert. Look inside the desert and you will find the ruins. Go inside and read the braille, and then use dig.the door should open.
TIPS (be sure 2 read):all of the caves will be a rock surrounded by smaller rocks. You will need relicanth in the first spot and Wailord in the last. ENJOY!!!
Sealed Chamber: Before you can get the regies you'll need to unlock the doors. Bring a pokemon that knows dive, a pokemon who knows dig, Relicanth, and Wailord. Surf West of Pacifidlog. Stay to the middle when some currents come eventually you'll run into a diving patch. Dive in. You're at the top of an Oval. Go to the bottom of the Oval. You'll see brail. Dive up. Go in the cave. At the top of the cave dig. A door will open. Step in. Now put Wailord first in your party and Relicanth last. Go to the top. Read the brail. There'll be an earthquake saying a door opened somewhere.
Regice: Surf down from the beach near Mr.Briney's house with 20 Ultraballs and 2-3 timerballs. After going down for a while you'll see an opening in the rocks. Now look for big rock with a door surrounded by six other rocks. Once you find that, go in. Now walk around the room staying close to the wall. A door will open. Go in. save the game. Fight Regice.
Regirock: Remember that desert? Your rival gave you glasses to go into it. Head into it with 20 Ultra balls and HM: Rock Smash. Head towards the bottom and you'll see a rock with a door and six rocks surrounding it. Go in. Go to the top. Now walk: left, left, down, down, and use rock smash. The door now has opened. Go in. Save the game. Fight regirock.
Or if you have pokémon emerald
Registeel: Go west of Lilycove with Flash and 20 Ultraballs. Keep going after seeing the Safari Zone. When you se a path up, go on it. You'll see the signature with the rock and the six rocks surrounding it. Go in. Go to the center and use Flash. Go in the newly opened door. Save the game. Fight Registeel.