No you do not need the regis to open sky pillar it is actually open before you even go to the Pokemon league and rayquaza starts on Lv. 70
You need to beat the Elite Four.
After you defeat Team Aqua and Team Magma's bosses, Wallace will take you to the Sky Pillar to awaken Rayquaza. Going through the incident in Sootopolis City, you can afterward return to the Sky Pillar to catch Rayquaza. This time, Sky Pillar will be more difficult to travel through, and Rayquaza is Lv. 70.
Sky Pillar will not open until it becomes essential to the storyline. Once this occurs, Wallace will meet you at Sky Pillar and grant you entry in order to awaken Rayquaza. After completing this event, Sky Pillar will remain open. From the second visit onwards, the Mach Bike is required to navigate to the top floor. Just go there after you get through Groudon and Kyogre's battle.
do the Pokemon leuge then talk to the weather dude and he will open two new places to fly to groudons cave and the sky pillar then fly to the sky pillar at the top raquazer awates
I don't think you can!
well in ruby and sapphire you need to beat all gyms and then beat the elite four then it should be open but in emerald you only need to beat the 8 gyms
Its sky pillar..once u go to sootopolis,u need to go to the cave of origin..once ur there,talk to wallace,then head to sky pillar..he will be there waiting for u ..once u talk to him,he opens the door for u to catch Rayquaza.
Go to sky pillar which is located on route 131 go to the top where you see raquaza and then he will fly to sootopolis. get out of sky pillar and fly to sootopolis and then.....
To go over the holes on sky pillar, you'll need a mach bike to run over it at full speed.
Go west from Route 129. You'll meet some trainers, continue on to Route 130, and find the Sky Pillar in the middle of Route 131. Sky Pillar will only be open to you after you defeat the Elite 4.
Fly,and waterfall
you deafeat Maxie @ Magma hideout and archie @ aqua hideout