Instructions
Capture both Relicanth and Wailord and add them to your Pokemon lineup. Relicanth can be captured on Route 124, 125 and 126. Wailmer can be captured on many different routes; you must raise your Wailmer to Level 40 for it to evolve into Wailord.
Surf west of Pacifidlog Town and use the Pokemon "Dive" move when you come to an opening in the currents.
Swim south and use "Dive" in front of the braille writing on the wall to enter the Sealed Chamber.
Use the Pokemon "Dig" move in the middle of the northern wall to create an opening. Walk through the opening to reach the second room.
Place Relicanth in the first position in your Pokemon lineup and Wailord in the last position.
Press "A" while standing next to the braille writing on the northern wall. An earthquake occurs and you hear the sound of three doors opening.
Travel to the cave northwest of Dewford Town and enter it; this cave is home to Regice, the first of the Regis. Stand in front of the braille on the northern end of the wall and do not move for two minutes. The door to Regice opens after two minutes have passed.
Enter the desert located on Route 111 and enter the tomb located in the southeast corner of the desert. Stand next to the middle section of the braille on the northern wall. Walk right two steps, down two steps and use the Pokemon "Strength" move to open the door to Regirock.
Travel to Lilycove City and use the western exit to reach Route 120. Walk north along the tall grass until you reach the cave entrance; enter, stand in the middle of the cave and use the Pokemon "Fly" move. The door to Registeel opens along the northern wall of the cave.