Things You'll Need
Instructions
S.S. Ticket
Proceed through the game until you've beaten the Elite Four and earned the National Dex. This is the last part of the game's main story arc, though "Pokemon Sapphire" features an abundance of post-victory activities. After the credits roll, your character will wake up in his bedroom.
Walk downstairs and speak with your father. He'll give you an S.S. Ticket. You can use this to go the Battle Tower, one of the game's most challenging post-victory features and a convenient place to level up Pokemon.
Go to Slateport City, on the southern end of the continent. Get there by traveling south on Route 110.
Speak with the sailor standing at the port on the eastern side of the city. He'll accept your S.S. Ticket and ferry you to the Battle Tower.
Eon Ticket
Acquire an Eon Ticket and an Eon Ticket Reader. Since these were released in 2003, they have become quiet rare. If you're lucky, you may be able to find one on an auction website such as eBay.
Defeat the Elite Four and earn the National Dex. Afterward, travel to Petalburg City, west on Route 102. Enter the Pokemon Center there and speak with the man standing by the computer. When he asks if you want to create a profile, select "Yes."
Choose the words "Mystery Event Is Exciting." This activates the mystery events, including the Eon Ticket. Save the game, then turn off your Game Boy.
Connect the Eon Ticket Reader to your Game Boy and turn it back on. When prompted, slide the Eon Ticket through the Reader. Choose "Mystery Events" and then follow the onscreen instructions. Load your game.
Exit the Pokemon Center and enter the Petalburg Gym, next door. Speak with your father inside, and he'll give you an in-game Eon Ticket. Take it to the Slateport City harbor to sail to the southern islands and capture the rare Pokemon Latios.