Type matchups and best counters for Onix in Pokémon Polished Crystal. Learn which Pokémon can effectively counter Onix and what types to use against it.
Types that deal increased damage to Onix. Use these types to counter it effectively.
Types that Onix resists or is immune to. Avoid using these types against it.
Pokémon that have type advantages against Onix, either offensively or defensively.