Grant's hints on catching the Regi - Guide for Pokemon Ruby

These are the steps Grant followed to catch his Regi:

1. How to find the 3 Regi

1.1 Open the 3 doors

To start, you need a Wailord and a Relicanth.  Fly to PacificLog Town and go along Route 132.  Eventually
you'll get to Route 133, and 134.  You'll find a small area surrounded by rocks. Use dive in the center.
Follow the underwater rift. Go to the ancient writing, and use dive again. It will say "sealed chamber".
Go to the front or top of the room, and use dig in the middle of the scripture.  Put a Wailord in the front
and a Relicanth in the back, or vice versa, and read the top scripture.  You should trigger an earthquake.
It will say "It sounds like 3 doors opened far, far away".

1.2 Regice

Go to Route 105, and find an island. There will be a ruin maniac on it.  Use surf until you get to a big
mountain.   There will be an opening.  Walk in and go to the top of the room.  Press "A" to read the scripture,
and wait without pressing any buttons for 2 minutes (Iused the clock timer on the microwave).  The door
to Regice's room will open.

1.3 Registeel

Go to Route 120, and go south until you find a bridge.  Cross the bridge, and walk south a bit more.  Look
for a stairway, and walk up the stairs.  Go through the grass to find another staircase.  You will find a
big mountain, go into the opening.  Go to the middle of the room and use fly. The door to Registeel will open.

1.4 Regirock

Fly to Lavaridge.  Bop down the mountain and into the desert.  Go down far and find a big mountain.
Go in the opening.  Walk to the top of the room, and go down 3 steps, and right 2 steps.  Use
strength and the door to Regirock will open.

2. Battling the Regi

2.1 The Order

The order doesn't matter, but the last one you fight will be the hardest, so choose wisely.  What I did was 
Regirock first, followed by Registeel and Regice last.  In the battle with Regice, the main Pokemon I used was
Registeel.  I used ancient power 4 times, then used false swipes (by Ninjask level 42), then I used an ultraball
and pressed "A" rapidly (I don't know why!), and caught it.

2.2 The first one

Get the Regi down to 1HP by using False Swipes.  Then, use Yawn to put it to sleep.  Use a few ultraballs
and you should catch it.

2.3 The second one

Get the Regi down to 1HP by using False Swipes, and use Yawn to put it to sleep.  Use ultraballs, and when
it wakes up, use another ultraball, and you should catch it.

2.4 The final one

Get it down to 1 HP by using False Swipes.  Have a Regi (it works best) use ancient power 4 times, then
use false swipes.  Use one to five ultraballs and you should catch it.

Warning: Save before you face them each time.  If they faint or you flee, turn off the GBA without saving,
so you can try again, without having to redo everything.

Good Luck!