Where to catch Voltorb

In Paldea (Scarlet & Violet)

• East Province (Area Three) — Walk
• West Province (Area One) — Walk
• West Province (Area Three) — Walk

In Hoenn (Ruby, Sapphire & Emerald)

• New Mauville — Static Encounter, Walk

In Johto & Kanto (Gold, Silver & Crystal)

• Olivine City — NPC Trade, Walk
• Route 10 — Walk
• Team Rocket Base — Static Encounter, Walk

In Kanto (Red, Blue & Yellow)

• Kanto Power Plant — Static Encounter, Walk
• Route 10 — Walk

Voltorb — full Pokédex entry