First you must beat snowpionts city gym leader the the 8th gym leader and then campion cinthya so after you do all that you got to get your pokedex full and talk the proffesor
To enter Snowpoint City's Temple you must first, defeat the Elite Four ,and second, you must have the National Dex. Inside you can catch,(if you have REGIROCK,REGIICE and REGISTEELin your party)drumroll please!,the legendary REGIGIGAS!
beat the game and go there oh ya ive almost fogot you need the nataral pokedex
the gyms are in the citys but some are harder to get into than others
You need to get further that the 4th gym leader to do that
No you can't. If you want to buy one then you can get them from the atheletes shop at the pokeathelon dome.
i find the easyest way is in every route keep walk around until you think you have caught all them in that area if you are want the to get the pokedex full just battle through out the main quest then go back to begining and go through the citys and towns for the missing Pokemon not the best answer but i hope you get what i mean :)
go to ever grande city and defeat Pokemon league. affter that go find these legendarys listed.rayquazalatiosregi'iceregirockregisteel.after you are through with that then go catch every Pokemon possible in Pokemon sapphire.after that trade with Pokemon ruby to get the Pokemon only in ruby. Then buy a gameshark for GBA. you need it to get Pokemon from difrent regions such as lugia ho oh celebi -etc. when you have every Pokemon from these regions,hoen,jhoto and kanto then go to lilycove citys game editor. he will give you the diploma. you have then beaten the game.
go to snowpoint and Canalave Citys
beat the elite four then go to snowpoint citys temple there will be a lady there and she will say no your not coming in then a nother lady will come and let you in
in the house beside enterna citys gym
the mineing meuseum in the city where roarks gym is ( i forgot what the citys called XD)
you surf to them
celastic and eterna
vertanturf and slateport
just about everywhere except citys
After you awaken Groudon
tropius.. pastoria citys great marsh =]
It will roll the credits. At this point, I thought it was over, but its not. wait a minute then ur able to access all towns citys again. u can go to the battle tower and do what you want to.
level up your Pokemon and get many full heals