Where to catch Arbok

In Kitakami (Scarlet & Violet – The Teal Mask)

• Fellhorn Gorge — Walk
• Mossfell Confluence — Walk
• Oni's Maw — Walk
• Reveler's Road — Static Encounter

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

Arbok — full Pokédex entry