While most trainers evolve Onix into Steelix immediately, the unevolved form has a niche with Eviolite boosting its defenses. Electric moves can't touch it, which offsets the 6 weaknesses somewhat. Can go either physical or special depending on the set. Part of the Gen 1 roster.
The stat bars tell the story: Defense carries everything and Sp. Atk's dead weight. But this Rock Snake Pokemon still yields 1 Defense EV per fight on a medium-fast 1M XP curve.
Burrows at high speed in search of food. The tunnels it leaves are used as homes by Diglett.
Onix Weakness
FragileOnix's Rock/Ground typing leaves it vulnerable to Water, Grass, Ice, Fighting, Ground, and Steel moves. Water and Grass hits land at 4x, so they're the biggest threat. It shrugs off Electric-type attacks completely. The Rock/Ground typing picks up 5 resistances to work with. Onix's physical bulk (base 160 Def) helps cushion physical weakness hits, but special attackers are the bigger threat.
To get Steelix from Onix, you need a trade. The evolution method matters here. The evolved forms gain up to 125 total stats over Onix.
How to Evolve
Breed Onix easily from the Mineral egg group.
Weakarmor and Eviolite give Onix staying power beyond its evolution stage. Careful nature boosts Sp. Def, max HP and Sp. Def EVs set the spread, and the pre-evolution bulk actually works here.
Best Build
Let's Go Pikachu & Eevee uses different battle mechanics.
Competitive build content is not applicable for this game. Select a main series game for builds.
The level-up pool tells the story here. Onix learns Earthquake and Iron Tail naturally, plus enough variety that TMs feel like bonuses. Normal and Steel coverage extends the reach beyond that.
Level-Up Moves
TM Moves
Egg Moves
Tutor Moves
A solid number of locations for Onix with moderate rates across early-game routes. The sort toggle below swaps between best odds and earliest access, so you can approach it based on where you are in the game.
Best Locations
10 walking encounters at Lv. 5-46 for Onix across Let's Go Eevee and Let's Go Pikachu. A few locations are version-exclusive, so your copy of the game affects what's available.
At 385 BST, Onix is firmly in pre-evolution territory. Evolve it into Steelix before bringing it to any serious fight.
Watch for Starmie (Water), Exeggutor (Grass), and Cloyster (Ice) when using Onix. They all hit it super-effectively with STAB. Starmie is the most dangerous since Water moves deal 4x damage. Fighting, Ground, and Steel-type attackers are also a problem. With 6 weakness types, most competitive teams carry at least one counter.
Onix evolves into Steelix while holding a Metal Coat. Onix is the base form of this evolutionary line.
Rock Head protects against recoil damage — that's the one you want on Onix. Weak Armor is the hidden ability. Niche, but it has its uses. Sturdy works too if your team needs something different.
Onix is a physical attacker with base 45 Attack. Enough bulk to take a hit or two, too. But the speed tells the real story — base 70 Speed is workable — faster than some, slower than many.
Onix appears in 21 games, including Yellow, Red & Blue, and Gold & Silver.
Present since Red & Blue, Onix appears in 21 games spanning 9 generations. Gen 1 originals like Onix have the longest track record of availability in the series.
- Gen IY
Yellow - Gen IRBDebut
Red & Blue - Gen IIGS
Gold & Silver - Gen IIC
Crystal - Gen IIIRS
Ruby & Sapphire - Gen IIIFRLG
FireRed & LeafGreen - Gen IIIE
Emerald - Gen IVPt
Platinum - Gen IVHGSS
HeartGold & SoulSilver - Gen IVDP
Diamond & Pearl - Gen VBW
Black & White - Gen VB2W2
Black 2 & White 2 - Gen VIXY
X & Y - Gen VIORAS
Omega Ruby & Alpha Sapphire - Gen VIIUSUM
Ultra Sun & Ultra Moon - Gen VIISM
Sun & Moon - Gen VIILGPE
Let's Go Pikachu & Eevee - Gen VIIISwSh
Sword & Shield - Gen VIIIPLA
Legends: Arceus - Gen VIIIBDSP
Brilliant Diamond & Shining Pearl - Gen IXSV
Scarlet & Violet - Gen IXLZA
Legends: Z-A