HT Games
Instructions
Go to Route 129 in the far east of Hoenn. Catch a wild Wailmer by fishing and evolve it into Wailord by getting it up to Level 40. Catch a Relicanth on Route 124 or 126 and set it as the last Pokemon in your traveling party of six. Set Wailmer as the lead Pokemon.
Go west to Pacificdlog Town and use a Pokemon's Surf move to head across the water to the west. Keep close to the southern side of the path and you will come across a cross-shaped patch of calm water, with a passage leading down to a cave. Go down the tunnel.
Go to the patch of braille writing on the back wall of the cave and use a Pokemon's Dig move in front of it. This will move you down into another cave, with more braille writing on the wall--read it to set off an earthquake. You can now swap Relicanth and Wailmer out of your party if you don't want to use them to fight the Regis.
Go to Route 111 in the center of Hoenn and head into the Sandstorm there. Go south and you will come to a cave entrance, which you can open using a Pokemon's Rock Smash move. Go inside and you will face a Level 40 Regirock. Use Grass, Water, Fighting or Ground-type moves to wear down its health points and catch it in a Pokeball.
Head to Dewford Town in the south west of Hoenn. Go north on Route 105 and you will see an island to the west of the path with a cave entrance on it. Use a Pokemon's Surf move to get over to the island and walk in a clockwise circle around the cave to open it. Inside is a Level 40 Regice. Wear down its health points using Fighting, Rock, Fire or Steel-type attacks and throw out a Pokeball to catch it.
Go to the Ancient Tomb on Route 120 in the north east of Hoenn and head inside. Use a Pokemon's Flash move in the middle of the tomb and an entrance will open at the rear. Head through it to encounter a Level 40 Registeel. Use Fighting, Fire and Ground-type moves to wear down its health points and catch it in a Pokeball.