Physical
Balanced
385Low
70Moderate
CTier

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.

Base Stats
385Avg
HP35
F
Attack45
D
Defense160
S
Sp. Atk30
F
Sp. Def45
D
Speed70
C
Total385
Low <60
Avg 60-89
High 90-149
Top 150+
EV YieldDefeating Onix yields +1 Def
HPAtkDef+1SpASpDSpe
Details
Catch45ChallengingMedium Fast1M XP8.8m / 28'10"210kg / 463 lbs77Base XP
Pokedex Entries

It twists and squirms through the ground. The thunderous roar of its tunneling echoes a long way.

Heart Gold

It rapidly bores through the ground at 50 mph by squirming and twisting its massive, rugged body.

Soul Silver

Onix Weakness

Fragile

Onix'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.

Gen IV Type Chart
  • Fairy type does not exist — Dragon has fewer checks
  • Physical / Special split now per-move (introduced Gen IV)
4xCriticali
¼xResisti
0xImmunei
6Weak
5Resist
1Immune
Scorei-7
SpikesGrounded — up to 25%
Toxic SpikesVulnerable
4x Water — Surf, Hydro Pump, Scald
4x Grass — Energy Ball, Giga Drain, Leaf Storm
Abilities
Rock HeadProtects against recoil damage.
SturdyPrevents being KOed from full HP, leaving 1 HP instead. Protects against the one-hit KO moves regardless of HP.
Weak ArmorHARaises Speed and lowers Defense by one stage each upon being hit by a physical move.

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

2 Forms
Onix
#095Onix
Trade + Metal Coat
Steelix
#208Steelix
Stat Comparison 2 Stages
Onix
RockGround
Steelix
SteelGround
HP
35
75+40
ATK
45
85+40
DEF
160
200+40
SP.ATK
30
55+25
SP.DEF
45
65+20
SPE
70
30-40
BST
385C-Tier
510C-Tier+125
ROLE
Balanced
Trick Room
TYPE
Utility
Physical
Breeding
Easy

Breed Onix easily with 29 breeding partners from the Mineral egg group. Pass egg moves like Block, Defense Curl, Explosion and 4 more to offspring.

Egg Groups
Mineral
Gender
50.0%50.0%
Hatch Time
25 cycles·6,425 steps
Moderate~6 min with Flame Body
Egg Moves
7moves
Breed With (best first)
glaliefroslasssnoruntporygon2claydolbronzongmagnezoneporygon-zprobopassgolemelectrodemagneton

One guaranteed turn is all Onix needs. Focus Sash buys it, max Attack and Speed EVs make it count, and Rockhead adds something extra. The goal: get Stealth Rock up and deal damage with Earthquake. Normal coverage gives it play beyond just the lead turn.

Best Build

Support
Ability
Rockhead
Item
Focus SashSURVIVAL
Nature
Jolly+SPE
EVs

Best Onix Moveset

  • Stealth RockSTAB
  • EarthquakeSTAB
  • ExplosionCoverage
  • ToxicUtility

The natural movepool does the job, but Block and Defense Curl from the egg pool give Onix something extra.

Level-Up Moves

Lv 1
Bind
157520Normal
Lv 1
Harden
30Normal
Lv 1
Mud Sport
15Ground
Lv 1
Tackle
3510035Normal
Lv 6
Screech
8540Normal
Lv 9
Rock Throw
509015Rock
Lv 14
Rage
2010020Normal
Lv 17
Rock Tomb
609510Rock
Lv 22
Sandstorm
10Rock
Lv 25
Slam
807520Normal
Lv 30
Rock Polish
20Rock
Lv 33
Dragon Breath
6010020Dragon
Lv 38
Curse
10Ghost
Lv 41
Iron Tail
1007515Steel
Lv 46
Sand Tomb
358515Ground
Lv 49
Double-Edge
12010015Normal
Lv 54
Stone Edge
100805Rock

TM Moves

Src
TM45
Attract
10015Normal
TM78
Captivate
10020Normal
TM28
Dig
8010010Ground
TM32
Double Team
15Normal
TM59
Dragon Pulse
9010010Dragon
TM26
Earthquake
10010010Ground
TM58
Endure+4
10Normal
TM64
Explosion
2501005Normal
TM42
Facade
7010020Normal
TM91
Flash Cannon
8010010Steel
TM21
Frustration
10020Normal
TM74
Gyro Ball
1005Steel
TM10
Hidden Power
6010015Normal
TM23
Iron Tail
1007515Steel
TM83
Natural Gift
10015Normal
TM66
Payback
5010010Dark
TM17
Protect+4
10Normal
TM77
Psych Up
10Normal
TM44
Rest
10Psychic
TM27
Return
10020Normal
TM05
Roar-6
20Normal
HM08
Rock Climb
908520Normal
TM69
Rock Polish
20Rock
TM80
Rock Slide
759010Rock
HM06
Rock Smash
4010015Fighting
TM39
Rock Tomb
609510Rock
TM37
Sandstorm
10Rock
TM43
Secret Power
7010020Normal
TM82
Sleep Talk
10Normal
TM76
Stealth Rock
20Rock
TM71
Stone Edge
100805Rock
HM04
Strength
8010015Normal
TM90
Substitute
10Normal
TM11
Sunny Day
5Fire
TM87
Swagger
9015Normal
TM12
Taunt
10020Dark
TM41
Torment
10015Dark
TM06
Toxic
8510Poison

Egg Moves

Src
Egg
Block
5Normal
Egg
Defense Curl
40Normal
Egg
Explosion
2501005Normal
Egg
Flail
10015Normal
Egg
Rock Blast
259010Rock
Egg
Rock Slide
759010Rock
Egg
Rollout
309020Rock

Tutor Moves

Src
Tutor
Ancient Power
601005Rock
Tutor
Block
5Normal
Tutor
Earth Power
9010010Ground
Tutor
Headbutt
7010015Normal
Tutor
Iron Head
8010015Steel
Tutor
Mud-Slap
2010010Ground
Tutor
Rollout
309020Rock
Tutor
Snore
4010015Normal
Tutor
Twister
4010020Dragon

Transfer Moves

Src
Gen 3
Body Slam
8510015Normal
Gen 3
Mimic
10Normal

Onix's scattered across 22 spots in early-game routes with high spawn rates. Check the list below for the closest location to wherever you are in the game. This one's quick.

Best Locations

walking and trade encounters for Onix across 22 spots at Lv. 6-48. The catch is that SoulSilver and HeartGold don't share every location, so compare what's available in your version.

Union Cave - B1F
SoulSilverGrassLv.8UncommonEarlyCave
EASY
Union Cave - B1F
HeartGoldGrassLv.8UncommonEarlyCave
EASY
Union Cave - 1F
SoulSilverGrassLv.6RareEarlyCave
CHALLENGING
Union Cave - 1F
HeartGoldGrassLv.6RareEarlyCave
CHALLENGING
Rock Tunnel - B1F
SoulSilverGrassLv.16UncommonMidCave
EASY
Rock Tunnel - B1F
HeartGoldGrassLv.16UncommonMidCave
EASY
Cliff Cave - 1F
SoulSilverGrassLv.20UncommonMidCave
EASY
Cliff Cave - 1F
HeartGoldGrassLv.20UncommonMidCave
EASY
Cliff Cave - 2F
SoulSilverGrassLv.20UncommonMidCave
EASY
Cliff Cave - 2F
HeartGoldGrassLv.20UncommonMidCave
EASY
Cliff Cave - B1F
SoulSilverGrassLv.20UncommonMidCave
EASY
Cliff Cave - B1F
HeartGoldGrassLv.20UncommonMidCave
EASY
Union Cave - B2F
SoulSilverGrassLv.23RareMidCave
CHALLENGING
Union Cave - B2F
HeartGoldGrassLv.23RareMidCave
CHALLENGING
Mt. Silver - 1F
SoulSilverGrassLv.42CommonLateCave
EFFORTLESS
Mt. Silver - 1F
HeartGoldGrassLv.42CommonLateCave
EFFORTLESS
Victory Road - 1F
HeartGoldGrassLv.34-36UncommonLateCave
EASY
Victory Road - 1F
SoulSilverGrassLv.34-36UncommonLateCave
EASY
Mt. Silver - Lower mountainside
SoulSilverGrassLv.48CommonPostCave
EFFORTLESS
Mt. Silver - Lower mountainside
HeartGoldGrassLv.48CommonPostCave
EFFORTLESS
Violet City
SoulSilverIn-game tradeLimitedCityTrade for (give Bellsprout)
LEGENDARY
Violet City
HeartGoldIn-game tradeLimitedCityTrade for (give Bellsprout)
LEGENDARY
  • 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.