Lugia locations — where to catch

In Paldea (Scarlet & Violet)

• North Paldean Sea — Static Encounter

In Johto & Kanto (HeartGold & SoulSilver)

• Whirl Islands — Static Encounter

In Sevii Islands (FireRed & LeafGreen)

• Navel Rock — Static Encounter

In Johto & Kanto (Gold, Silver & Crystal)

• Whirl Islands — Static Encounter

Other games (4)

• Ultra Sun / Ultra Moon (Gen 7): Ultra Space Wilds, Ultra Space
• Omega Ruby / Alpha Sapphire (Gen 6): Sea Mauville
• XD (Gen 3): Citadark Isle
• Emerald (Gen 3): Navel Rock

Lugia — full Pokédex entry