After you get the Rain Badge in Sootopolis Gym, you can use Waterfall outside of battle, which allows you to reach the base of Ever Grande City and enter Victory Road.

Prepare

In Victory Road, you will need to bring pokémon that know Strength, Flash, Surf, Waterfall, and Rock Smash.

How to Get to Victory Road

To reach Victory Road, you have to have all eight gym badges. Teach Waterfall to one of your pokémon, then surf south from Mossdeep City until you reach Route 128. Go east from there to reach the base of Ever Grande City. Go up to the waterfall in the north part of the area and use Waterfall to go up. Then you can go into the Pokémon Center in the east part of the area, and when you are ready you can go north into the entrance of Victory Road.

Catch Pokémon

Where you first enter Victory Road, you can catch Zubat, Golbat, Whismur, Loudred, Makuhita, Hariyama, Aron, and Lairon. In B1F, you can catch Golbat, Hariyama, and Lairon. In Ruby and Sapphire, you can also catch Meditite and Medicham. In Emerald, you can catch Mawile. You might also encounter Geodude and Graveler when using Rock Smash. In B2F, you can catch Golbat and Lairon. In Sapphire and Emerald, you can catch Sableye. In Ruby and Emerald, you can catch Mawile. In Ruby and Sapphire, you can catch Medicham. You can also encounter Golbat by Surfing. If you use the Old Rod, you can catch Magikarp and Goldeen. If you use the Good Rod, you can catch Goldeen, Magikarp, and Barboach. If you use the Super Rod, you can catch Barboach and Whiscash.

Victory Road 1F

From the entrance of Victory Road, if you want a Max Elixir, go north, then when you reach stairs, go left and north, then east. Go up the stairs, then go east across the bridges, and go down the stairs to find the Max Elixir. From there, jump down the ledge and go south, then west. If you feel like battling the trainer (Cooltrainer Albert, who has Muk, and Manectric in Ruby/Sapphire and Magneton in Emerald), you can go west past him and up the stairs, then cross the bridge and go down the stairs. From there, go northeast and up the stairs, then west across the bridge, then north and battle Cooltrainer Hope, who has Roselia. Then go down the ladder near her.

If you got the Max Elixir but you want to avoid Cooltrainer Albert, go north from where he is standing, then all the way to the west, then south, then up the stairs then west across the bridge, then north and battle Cooltrainer Hope, who has Roselia. Then go down the ladder near her.

If you don't want the Max Elixir, then go north, then up the stairs then west across the bridge, then north and battle Cooltrainer Hope, who has Roselia. Then go down the ladder near her.

Victory Road B1F

Use Flash to light up this area. Go south and then west. Use Strength to push the boulder to the left. Go south from there and follow the path to the next boulder. Push it to the right, then go south, then east.

If you want a PP Up, go north and break the two jagged rocks, then push the first boulder down and the second boulder up. Go east and then south. You will encounter Cooltrainer Shannon, who has Claydol. Then go south from her, then east and up the stairs. Go east across the bridge, then go south and down the stairs. Go up the ladder there and get the PP Up. Then go back down the ladder. If you want a Full Restore after that, go north and battle Cooltrainer Samuel, who has Dodrio, Lairon, and Kadabra. Then go north from him and push the boulder up, then left. Then push the next boulder left. Use Rock Smash on the jagged rock, and get the Full Restore.

If you don't want the aforementioned PP UP, but you want a Full Restore, go east and use Rock Smash on the one jagged rock that is there. Go east from it and up the stairs, then go east across the bridge and go down the stairs at the end. Go east and battle Cooltrainer Samuel, who has Kadabra, and Dodrio and Lairon in Ruby/Sapphire, or Swellow and Mawile in Emerald. Then go north from him and push the boulder up, then left. Then push the next boulder left. Use Rock Smash on the jagged rock, and get the Full Restore.

If you don't want the PP Up or the Full Restore, you will still have to battle either Cooltrainer Samuel, who has Kadabra, and Dodrio and Lairon in Ruby/Sapphire, or Swellow and Mawile in Emerald; or Cooltrainer Shannon, who has Claydol.

If you aren't getting the PP Up or Full Restore and you want to battle Shannon, then to reach Shannon, go north and break the two jagged rocks, then push the first boulder down and the second boulder up. Go east and then south. You will encounter Cooltrainer Shannon, who has Claydol. To reach the next floor after battling her, go south, then east and up the stairs. Go east across the bridge, then go south and down the stairs. Then go west down the ledge and go west to reach the ladder to the next floor.

If you aren't getting the PP Up or Full Restore and you want to battle Samuel, then to reach Samuel, go east and use Rock Smash on the one jagged rock that is there. Go east from it and up the stairs, then go east across the bridge and go down the stairs at the end. Go east and battle Cooltrainer Samuel, who has Kadabra, and Dodrio and Lairon in Ruby/Sapphire, or Swellow and Mawile in Emerald. To reach the next floor after battling him, go all the way south, then go west to reach the ladder to the next floor.

Victory Road B2F

Go north and battle Cooltrainer Julie, who has Sandslash and Ninetales. In Emerald, she also has Tropius.

If you want TM29 Psychic, go north and surf to the northeast stairs. Go up and then east, then north to reach a ladder. After you go up the ladder, go south to find TM29. After that, go north and down the ladder again. After that, if you want to battle more trainers, go south to battle Cooltrainer Owen who in Ruby/Sapphire has Kecleon, Rhyhorn, and Tentacruel, and in Emerald has Kecleon, Graveler, and Wailord. Then go south and then west across the bridges.

In Emerald, you will find Cooltrainer Dianne, who has Claydol and Lanturn, and Cooltrainer Felix, who has Medicham and Claydol. If you walk between them, they do a double battle against you.

Keep going west to battle Cooltrainer Caroline, who in Ruby/Sapphire has Mawile and Sableye, and in Emerald has Skarmory and Sableye. From there, go north and use Surf in the water.

If you don't want TM29 Psychic, then go north from Cooltrainer Julie and use Surf to reach the waterfall to the northwest. Use Waterfall to go up to the upper area.

In this upper area of water, you can get a Full Heal if you go to the middle area and battle Cooltrainer Vito, who in Ruby/Sapphire has Swellow, Kadabra, Manectric, and Shiftry, and in Emerald has Dodrio, Kadabra, Electrode, and Shiftry.

Otherwise, surf west and go down the waterfall, then go east and go up the ladder there.

If you are playing Emerald, you will see Cooltrainer Mitchell and Cooltrainer Halle here. If you walk between them, they do a double battle against you. Mitchell has Lunatone and Solrock, and Halle has Sableye and Absol.

You can battle an optional trainer by going west down the ledge. You will find Cooltrainer Michelle, who in Ruby/Sapphire has Nosepass, Medicham, and Ludicolo, and in Emerald has Torkoal, Medicham, and Ludicolo. After battling her, go south from her and go down the ladder, then go east down the ledge, and go north to the water, where you can go back up the ladder that you went up before.

If you don't want to battle the optional trainer mentioned in the previous paragraph, go south and then east. Break the rock with Rock Smash, then push the boulder down with Strength. Break the second rock, then go north to the ladder.

You're back in 1F now. Just follow the path until you reach Cooltrainer Edgar, who has Cacturne. In Emerald, he also has Pelipper.

Go north. In Emerald, you will encounter Cooltrainer Katelynn and Cooltrainer Quincy. If you walk between them, they do a double battle against you. Katelynn has Gardevoir and Slaking, and Quincy has Slaking and Dusclops.

Battle Wally

Go north and you find Wally. He has an Altaria, Delcatty, Roselia, Magneton, and Gardevoir.

Altaria is weak to Rock and Dragon moves, and very weak to Ice moves. Wally's Altaria has the Natural Cure ability, which cures any status ailments if the pokémon is switched out. It knows the move Safeguard, which protects Wally's pokémon from status ailments for five turns. It also knows a Flying attack and a Dragon attack.

Delcatty is weak to Fighting moves and is immune to Ghost moves. It knows Sing, so it can inflict Sleep on your pokémon. It knows Assist, which allows it to use any move that any of Wally's pokémon know. It has the Cute Charm ability, which has a chance of inflicting Infatuation on your male pokémon when either pokémon uses a move that makes contact.

Roselia is weak to Fire, Flying, Psychic, and Ice moves. It knows several Grass attacks and also knows Toxic, which can cause bad poisoning. It has the Poison Point ability, which has a chance of poisoning your pokémon when either pokémon uses a move that makes contact.

Magneton has the Magnet Pull ability, which prevents you from switching pokémon during the battle. It is weak to Fighting and Fire attacks, and very weak to Ground attacks. It is immune to Poison attacks. It knows an Electric attack, and it knows Tri Attack, which has a chance of inflicting Paralysis, Freeze, or Burn. It also knows Supersonic, which can cause confusion.

Gardevoir is weak to Bug, Ghost, and Dark moves. It has the Synchronize ability, which causes your pokémon to suffer the same status ailment if you inflict a status ailment on Gardevoir. Gardevoir knows a Psychic attack, as well as Future Sight, which causes damage two turns after it is used, and can even damage a pokémon with the Wonder Guard ability.

Go to the Pokémon League

After you defeat Wally, you can go north and exit the cave. Go north from there to reach the Pokémon League. After you enter the Pokémon League, you can come back to it any time using Fly.