Things You'll Need
Instructions
Play "Pokemon LeafGreen" and catch a Larvitar in Seavault Canyon, an area on Quest Island. Seavault Canyon is to the north of the Tanoby Ruins. Level 15 to Level 20 Larvitar roam in the grassy patches of the area.
Train the Larvitar to Level 30. Once the Larvitar reaches Level 30, it will evolve into a Pupitar. Make the Pupitar earn enough experience points to reach level 55, at which point it will transform into a Tyranitar. Save your progress in "Pokemon LeafGreen."
Borrow a Game Boy Advance from a friend. Insert "Pokemon LeafGreen" into your GBA, and insert "Pokemon Sapphire" into the borrowed GBA. Plug one end of the GBA Link Cable into one system, and plug the other end into the borrowed system.
Load the save file in both GBA games. Go to the PokeCenter or Pokemon Network Center in "Sapphire" and "LeafGreen." Choose to trade the Tyranitar in "LeafGreen." Select any Pokemon to trade in "Sapphire." After a few minutes, the exchange will be complete.