What you need:
-The Elite Four beaten
-Plenty of Ultra Balls
-some Timer Balls (for when the Ultra Balls run out)
-Some Dive Balls
-Dig
-Surf
-Strength
-Dive
-Fly
-Relicanth
-Wailord
You can catch a Relicanth underwater, but they are rare. I would recommend using Dive Balls and a Pokemon that can put Relicanth to sleep. You will also likely want the Pokemon that can put to sleep while battling the Regis. Wailords can be found on route 129 whilst Surfing.
Now fly to Pacifidlog Town and surf west until you find an area where you can Dive. Head through the door and to the end of the tunnel where there is some Braille. Now use Dive again to surface in a cavern.
Here walk to the back wall and stand in the middle of the Braille and use Dig. A door will appear. Go through.
In this cavern place your Relicanth in first place and your Wailord in last place. There will be an earthquake and you will be told a door has opened far away. Now it's time to go and catch some Regis! You will not need your Relicanth or Wailord again.
REGIROCK!
Fly to Lavaridge. Walk east and then north into the sandstorm. To the south of this sandstorm is a large rock with a cave entrance. Go in, walk up to the Braille, and read it. From the middle of the Braille walk two steps right and two steps down. Use Strength. A door should have opened. Go in!
Press A on Regirock to battle it. Simply work its health down low and capture with one of the many Ultra Balls you brought along. (I know it is tempting to go into battle unprepared but I got this Pokemon down to a tiny sliver of health and put it to sleep and it still took me more than 30 Ultra Balls to catch.)
REGICE!
Fly to Dewford. Surf north along Route 106 onto Route 105. On the west edge of Route 105 is an island to cross. Surf north to find the large rock with a cave entrance. Go in, read the middle bit of Braille, and wait for two minutes without moving. The door will open. (Some websites tell you to go out and back in or to walk around the edge of the room or to read all three sections but if you just read the middle one and wait it will open.)
Then repeat the catching procedure on Regice.
REGISTEEL!
Fly to Lilycove. Walk west past the Safari Zone until you reach some steps. Walk through the grass into a rainy area with a large rock with a cave entrance. Go in and read the Braille. From the middle of the Braille, walk 4 steps down. This should be the middle of the room. Use Fly. A door should open. Go in!
This Pokemon is VERY hard to catch. Harder than the other two Regis by far. I had to turn off my Gameboy when I had used all 50 of my Ultra Balls and still hadn't caught it. It was asleep at this stage; I should have used Timer Balls.
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The above is accurate; just as a bit of advice, however: it is crucial to use Timer Balls. I caught all three of mine with Timer Balls simply because 1) they become much more effective as time passes and 2) when trying to capture the Regis you can be very sure a lot of time will pass. It will help you conserve your Ultra Balls. Of course, you should still start with Ultra Balls; Timer Balls do not start becoming truly effective until around the 30th turn.
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Warning: do not rename these Pokemon. If you plan on trading to pearl to make a certain Pokemon you will need these three Pokemon with their ORIGINAL names.
Regirock:Two left,two down,rock smash
wrong two rigt sand two downand us strengt noob!
This just in: The Regis can be obtained before you kick Pokemon league butt; i used them to beat the League you just need Relicanth and Wailord but Relicanth is hard to find. Just make sure that when you come across him you have at least 5 dive balls cause other balls wont catch him. First you need A Relicanth and a wailord, go to Pacifalog Town and surf into the rapids, when you get to the deep area dive and go into the cave, read the brail at the end of the cave, dig through the wall, then go to the end of this room and put Relicanth in 1st, and Wailord in 6th. then you will here 3 crys, all of them from the Regis.
Regirock is in the desert North of Mauvile City. Regice is on one of the island between Dueford Town and Petelburg City. Registeel is on Route 119. to find out the exact location look on the Pokenav's map. the relicanth can be found by diving at the entrance to sootopolts city an going through the seaweed. It is very rare to find one. I suggest to trade a good Pokemon to a freind for a relicanth
Go to serebii.net but before you do get a wailord and a relicanth. Remeber: there are different ways to get the regi's depending which Pokemon game you have but for sapphire, ruby and emerald that's the first part.
Unfortunately, you must migrate the regies from ruby or sapphire. You cannot catch them in pearl/diamond.
you need to migrate them from either ruby,saphire,or emerald at palpark.
You can't find it at Pokemon Pearl you have to Transfer it from the GBA Games Ruby/Sapphire/Emerald via Pal Park
If you want Regirock, Regice, and Registeel on Diamond, you'll need to trade from Platinum, or migrate from Ruby, Sapphire, or Emerald.
OK the rare Pokemon are groundon, i think there's the 3 regies regirock,regiice,registeel. And you can also get this strong Pokemon named milotic. But you need to evolve it from feebas though. hoped this helped!:)
you must trade them
you cant. you have to trade them from Pokemon emraled.
you need to have the national pokedex
Trade or wait for an event.
Yes you do.
u cant u can only get them from sapphire; emerald or ruby.
you can use cheats or have a regigigas from the 11th movie