How to Catch Bagon in Pokemon Emerald

Get the HM07 Waterfall

Explore the plot and get the Mind Badge. You'll need to explore most of the game's plot before you can get Waterfall. This Hidden Move is required to enter the area where you can find the Bagon. Waterfall allows you to wade up waterfalls around the world. You will obtain the Mind Badge item in Mossdeep City.

Fight Team Aqua (water team members) in Seafloor Cavern. After getting the Mind Badge, you will have the ability to use Dive while moving. Use this move in the deep blue water south of Mossdeep city to find the Seafloor Cavern.

Continue via Route 126 until you reach Sootopolis. If you've ever been to Sootopolis, you can use the Fly move to quickly get there. Search for Coach Steven in North Sootopolis City (city).

Go to Cave of Origin. You will be asked by Steven to search for Coach Wallace in the Cave of Origin. Talk to Wallace and answer "SKY PILLAR".

Go to the Sky Pillar and look for the legendary Pokémon Rayquaza at the top of the Pillar. You can reach Sky Pillar from Pacifidlog Town (town). Rayquaza will fly away in the direction of Sootopolis City. Use Fly to fly along.

Watch the flying scene then head to Sootopolis Gym (gym). You will see Rayquaza fighting the legendary Pokémon Groudon and Kyogre, then it will fly away. Talk to Steven outside the Sootopolis Gym and then talk to Wallace. Wallace will give you item HM07 as thanks for rescuing the town.

Defeat head trainer Juan in the Sootopolis Gym. Once you get the Waterfall, you won't be able to use it outside of battle until you get the Rain Badge item from the Sootopolis Gym. This is the final Gym in the game, so make sure you're fully prepared for the fierce battle. After getting the Rain Badge, you will be able to use Waterfall around the world.

Search Bagon

Go to Meteor Falls cave. According to the story, you entered this cave before, so use Fly to Fallarbor Town to quickly get to Meteor Falls cave. This cave is located between Route 114 and 115.

Surf the water to the right of the entrance. After entering Meteor Falls cave, you will see a water tank. Go north and use the move (Surf) to surf on the water.

Use HM07 Waterfall to wade up the large waterfall. Approach the waterfall and press "A" to see a message asking if you want to use the Waterfall.

Enter the cave at the top of the waterfall. After climbing the waterfall, you will see a small plot of land and the entrance to the cave. Land on this small patch of land and walk through the entrance.

Go north and climb down the ladder. Head right then up a bit to find the ladder. Then climb the ladder downstairs.

Go to the northwest corner of the cave and climb the ladder. You will be challenged by a duo of coaches. After defeating them, climb the ladder to the top of the room.

Jump down over the reef, heading left. The ladder you need to find is in the lower left corner of the room. Jump down across the reef and head left to reach the ladder.

Climb down the ladder and surf on the water. Go to the north side of the room and land on the patch of ground with the cave entrance.

Enter the cave and glide to the top of the room. This room is long and narrow so you will need to skim the water in the room. Land on the small patch of ground at the top of the room.

Walk around the small plot of land until you reach Bagon. This small, arid patch of land is the only area in the entire game where you can encounter the Pokémon Bagon. Bagon has a 20% chance of appearing when you encounter a wild Pokémon here, so you may need to fight several battles until you see it appear.

Catch the Pokémon Bagon

Use a Pokémon with False Swipe to reduce Bagon's health. False Swipe is a suitable move for catching Pokémon, as it can reduce a wild Pokémon's health to 1 HP but will never cause it to die. Farfetch'd, Cubone, Scizor and Nincada are some of the Pokémon that can learn this move by leveling up, or you can use the item TM54 to teach it to another Pokémon.

If you don't own a Pokémon with False Swipe, you can use a regular move to reduce Bagon's health as much as possible without causing it to collapse.

Use Sleep or Paralyze to trap Bagon. These moves will increase the probability of catching a Poke Ball's Bagon (ball containing Pokémon). There are many Pokémon that can learn moves that cause these status effects, and it's likely that you already have at least one of them.

Throw the Ultra Ball to have the highest probability of catching a Bagon. Ultra Ball (Hyper Ball) is expensive but can catch Bagon easier than other balls. If you have reduced Bagon's health to 1 HP and put it to sleep or paralysis, almost any Poke Ball can capture it.