Sootopolis City is a location in the Pokemon series of video games, which is only found in the Ruby, Sapphire, and Emerald games. In order to get to the city, the player must have a Pokemon which has been taught Dive. It can then be accessed via Route 126.
there are lots of ways to get fire stones. the one i do is once you get the hm dive, there is an area yu can go underwater, you find items and one item you find is shards, they come in different colors, wen you find a red one theres a house by sootipolis in a little island the guy trades you the red shard for a fire stone. its pretty difficult good luck:)
if this is for blue you have to beat team aqua in their under water cave on route 128 use dive in the underwater trench then find a cave with a sub in it dive up in the cave then solve the mazes[ wich is pretty hard u need surf, strength and rock smash.]then after u beat the boss kyrogre dissapears then go to the cave in sootipolis[u will notice the old man is gone.]and go in. battle kyogre[ but don't actullay hurt it at all.]then use the master ball first thing.[it never fails!:)]then go to the gym. the gym is tricky. the trick is to not step one the same peice of ice twice. if you do you fall and have to battle a bunch of chicks.[ i mean like girls not really chicks]. your welcome! :):):):):):):):):):):):):):):):)::):::):):):):) oh! if ask were can u find him: u have to go under water with dive then go in a cave then go up using dive and walla! sorry if i didnt answer he question correctly!
Heartgold/SoulSilver/Yrystal: go to the weather institute.talk t0o the guy who gve castform after deafeating the elite 4.and then he'll tell u where groudon is.Then kill or catch groudon.Then go to the weather institute again.and the guy who gave the castform will tell u where kyogre is.groudon is in terra cave and kyogre is in marine caveSapphire/Ruby/Emerald:go to the cave of origin in sootipolis city and catch it. It is inside a cave so bring a lot of max repel. First go into the cave and keep on going foward up the ladder. Then use flash, walk around until you see a ladder. Keep doing this until this your third time doing this. If you find HM08 waterfall, you are on the right track so keep on going right up the ladder. There you should find kyogre. It is at lv.45 and is very tough. Use your best physical moves like thunder punch and low kick due ti its awesome sp. def and heaviness. I recommend NOT using your Master ball. Best of luck!After beating the elite four go to the weather institute and talk to the man upstairs after you do the same thing withgroudon ( it tells you that there's a drought for groudon, and a drizzle for kyogre) It will tell you what route he's on go to that route. (be aware he is always on water) you will see a dive spot make your Pokemon use dive and swim around in the water and eventually you will see a cave go in and dive up. You will be at the entrance of the marine cave. Walk through it and you will eventually see kyogre in the water. he will be at level 70. Have a lot of net balls as they work well against water types. go to the cave of origin in sapphire or get it on a trade migrate from ruby,shappire or emerald