From Fuchsia City, head south onto Route 19, then Route 20. You'll need the 'Sea Skim' Secret Technique (equivalent to HM Surf) to travel across the water. Your Partner Pokémon will learn this from a man in Fuchsia City. These routes lead to the Seafoam Islands, a large cave system. The main goal here is to push large boulders into holes to block the strong currents, allowing you to reach the legendary Pokémon Articuno. Be prepared for Ice-type Pokémon and trainers.
