Where to catch Magneton

In Paldea (Scarlet & Violet)

• Dalizapa Passage — Walk
• Glaseado Mountain — Walk

In Blueberry Academy (Scarlet & Violet – The Indigo Disk)

• Canyon Biome — Walk, Static Encounter
• Chargestone Cavern — Walk
• Polar Biome — Walk

In Hoenn (Ruby, Sapphire & Emerald)

• New Mauville — Walk

In Johto & Kanto (Gold, Silver & Crystal)

• Kanto Power Plant — NPC Trade, Trade

In Kanto (Red, Blue & Yellow)

• Cerulean Cave — Walk
• Kanto Power Plant — Walk

Magneton — full Pokédex entry