Slowbro locations — where to catch

In Lumiose City (Legends: Z-A)

• Jaune Sector 10 — Static Encounter
• Wild Zone 11 — Walk
• Wild Zone 12 — Static Encounter

In Paldea (Scarlet & Violet)

• Casseroya Lake — Walk, Static Encounter
• Socarrat Trail — Walk
• West Province (Area Three) — Walk
• West Province (Area Two) — Walk

In Johto & Kanto (HeartGold & SoulSilver)

• Johto Safari Zone — Walk
• Seafoam Islands — Surf
• Slowpoke Well — Surf

In Kanto (FireRed & LeafGreen)

• Cerulean Cave — Surf
• Cinnabar Island — Super Rod
• Seafoam Islands — Surf, Walk

In Sevii Islands (FireRed & LeafGreen)

• Berry Forest — Surf
• Cape Brink — Surf, Walk

In Johto & Kanto (Gold, Silver & Crystal)

• Slowpoke Well — Surf

In Kanto (Red, Blue & Yellow)

• Cerulean Cave — Super Rod
• Route 12 — Surf
• Route 13 — Surf
• Route 23 — Super Rod
• Seafoam Islands — Walk

Other games (5)

• Sword / Shield — The Isle of Armor (Gen 8): Max Lair
• Let's Go, Pikachu! / Let's Go, Eevee! (Gen 7): Seafoam Islands
• Ultra Sun / Ultra Moon (Gen 7): Kalae Bay
• Sun / Moon (Gen 7): Kalae Bay
• Black / White (Gen 5): Abundant Shrine

Slowbro — full Pokédex entry