Arbok locations — where to catch

In Lumiose City (Legends: Z-A)

• Bleu Sector 10 — Static Encounter
• Lysandre Labs — Walk, Static Encounter
• Rouge Sector 8 — Walk
• Wild Zone 10 — Walk

In Kitakami (Scarlet & Violet – The Teal Mask)

• Mossfell Confluence — Walk
• Reveler's Road — Static Encounter

In Sinnoh (Diamond, Pearl & Platinum)

• Great Marsh — Walk

In Johto & Kanto (HeartGold & SoulSilver)

• Johto Safari Zone — Walk
• Route 26 — Walk
• Route 27 — Walk
• Route 3 — Walk
• Route 4 — Walk

In Kanto (FireRed & LeafGreen)

• Route 23 — Walk

In Johto & Kanto (Gold, Silver & Crystal)

• Mt. Silver — Walk
• Route 26 — Walk
• Route 27 — Walk
• Route 28 — Walk
• Route 3 — Walk
• Route 4 — Walk
• Route 42 — Walk

In Kanto (Red, Blue & Yellow)

• Cerulean Cave — Walk
• Route 23 — Walk

Other games (3)

• Ultra Sun / Ultra Moon (Gen 7): Alola Route 8
• X / Y (Gen 6): Kalos Route 19
• XD (Gen 3): Cipher Key Lair

Arbok — full Pokédex entry