Where do you catch rayquesa?

He is at the very top (summit) of Sky Pillar. You will need the Bike that goes at great speed, so if you don't have that now, go back and swap it at the shop in Mauville.

Head right from Pacifidlog town and make sure to stay up. Eventually you will find a gap in the rocks, then go left and up, this is Sky pillar.

Continue to go up and ride the bike quickly over and through the gaps, figure it out and don't lose your coool and you will reach the top, where Rayquazza sits, waiting.

Good luck, he is level 70 and knows Fly, so use either the Mster ball, or a lot of Ultra/Timer balls.

1st, you have to beat the Elite 4. Then go to Pacifidlog Town and surf to thr right. You will see that the rocks have a little opening now, go there and there will the Sky Pillar. Go all the way to the top and Rayquaza will be there, and it is hard to catch.

I will go into detail even if it's already answered O_O b

Requirements: 1. A Pokemon or 2 strong enough to combat lvl 70 RAYQUAZA, not RAYQUESA
2. 1 master ball, or around 15-25 ultra balls to catch it if you want
3. The MACH Bike, not ACRO
4. A Pokemon that knows surf

Now that you have all this junk, fly to pacifilog town or whateva it is. There? Good. Now start surfing north and then start going east... Once you reach an area where there is a gap where you can continue to farther up, go there. It'll lead to the SKY PILLAR, home of rayquaza once you finally beat that bas**** steven. Now go up to the second floor, and you'll need your mach bike to go across the cracks. Continue up once you finish, and you'll need your mach bike again on level 4. Once you get all the way to the end and go down one of the 2 cracks in the MIDDLE, not all the way in the end, continue up the last two floors there is 23 ft large rayquaza! Have fun getting killed =)

He is at the top of the sky pillar you will need the mach bike to get to him

First, you will need the Mach Bike, Surf and a lot of Pok� balls/Ultra Balls, etc.

Go to Pacifidlog Town and surf east to Route 131. Stick close to the rocks at the top and you should see a small island (I forget exactly where it is now, but I'm sure you can figure it out on your own).

When you do get on the island, go into the tower and use the Mach Bike to get across the cracks in the ground.

Keep going up and figure out the stupid little puzzles and you should eventually make it to Rayquaza. BE SURE TO SAVE BEFORE BATTLING HIM. He will be at level 70. (It took me quite a while to catch him.)

P.s: I've done this a long time ago, so I'm not 100% sure about it and I apologize if I've made a mistake, but I hope I've helped.