Some use cheats. Others just give up. But some are determined to get them. That's right, get the Ryogi Trio. Read this article and follow its directions to get your hands on Regirok, Regais and Register in Pokemon Emerald without any cheat codes.
Steps

Step 1. Capture the Relicant
The Wild Relicant can be found underwater near Sootopolis City. All you need to do is dive under the water and find him in the seaweed thickets. It may take some time to find the Relicant, since you will mainly come across Klamperl, but after a few meetings, one Relicant will still appear. Catching the Relicant is best done with dive or netballs, because other Pokeballs have a rather low chance of catching it.

Step 2. Catch Wilord
The chances of meeting a wild Wilord are very small, so it would be better to swing Wilmer to level 40. They can be caught with the Super Rod near Dewford Town. It is best to catch them with the same netballs.

Step 3. Go to the city of Pasifidlog
Apply the Surf skill and find the place where the current begins. Swim along it until you find a dive site near Route 134. Use the Dive ability. You will find yourself at the entrance to the cave. Go inside. In front of you will be a cave with stone slabs on which something is written in Braille. Go to the far end of the cave and stand in front of the central slab. You will need a Pokémon with the Dig skill. Now put Wilord as your main Pokémon and Relicant as the last. Use the ability Dig. After that, an earthquake will occur.

Step 4. Catch the Regirok
Fly to Lavaridge Town or an area near the desert. Regirok's crypt is located south of the desert. Go inside. Now go to the back wall of the cave. Then take two steps to the left and then two steps down. Use the Rock Smash ability. The wall should open. Inside you will have a level 40 Regirok.

Step 5. Catch Regais
Now that you've caught Regirok, it's time to catch Regais. Head to Petalburg City or Dewford Town and then onto Route 105. This is where Regais's Cave is located. Once inside, walk clockwise, keeping close to the wall. After that, the door will open. Inside you will be waiting for a level 40 Regais.

Step 6. Catch Registers
Next on the list is Registered. Catching this Pokemon will be the hardest part. His cave is on Route 120, so you need to head to Fortree City. When you find yourself inside the cave, go to its center and use the Flash ability. After that, the door will open. Inside you will be waiting for the Level 40 Registered.

Step 7. Congratulations on capturing the Three Rega
If you own the Diamond, Pearl or Platinum versions of the game, you can move the Trio through Pal Park and catch Regigigas! (Note: Pal Park will only open after you complete the main story and see all the Pokémon in Sinnoh).
Advice
- Take a lot of Repels with you to keep wild Pokémon out of your way.
- Take a Pokémon of the same level with Ryoga with super-effective skills to weaken them.