Mixed
Hazard Setter
525High
70Moderate
BTier

Nothing about Cloyster screams competitive powerhouse, and that's fine. Water/Ice means only weak to Electric, Grass, Fighting, and Rock. An original Gen 1 pick. Needs some investment to avoid getting outsped.

Defense leads and Sp. Def gets almost nothing. That's Cloyster's stat line in a nutshell. 3 stats sit in respectable range, but the spread is brutal. Moderately hard to find and yields 2 Defense EVs.

Base Stats
525High
HP50
D
Attack95
B
Defense180
S
Sp. Atk85
C
Sp. Def45
D
Speed70
C
Total525
Low <60
Avg 60-89
High 90-149
Top 150+
EV YieldDefeating Cloyster yields +2 Def
HPAtkDef+2SpASpDSpe
Details
Catch60Challenging•Slow1.25M XP•1.5m / 4'11"•132.5kg / 292.1 lbs•184Base XP
Pokedex Entries

Its shell is extremely hard. It cannot be shattered, even with a bomb. The shell opens only when it is attacking.

Fire Red

When attacked, it launches its horns in quick volleys. Its innards have never been seen.

Leaf Green

Cloyster Weakness

Vulnerable

Cloyster's Water/Ice typing leaves it vulnerable to Electric, Grass, Fighting, and Rock moves. Cloyster's physical bulk (base 180 Def) helps cushion physical weakness hits, but special attackers are the bigger threat.

Gen III Type Chart
  • Dark and Steel types added — Fairy does not exist yet
  • Moves are Physical or Special based on type, not per move
4xCriticali
None
2xWeaki
ElectricGrassFightingRock
½xResisti
Water
¼xResisti
Ice
0xImmunei
None
STAB (6)i
FireGroundRockGrassFlyingDragon
4Weak
2Resist
0Immune
Scorei-5
Stealth Rock25% on switch
SpikesGrounded — up to 25%
Toxic SpikesVulnerable
Abilities
Shell ArmorProtects against critical hits.
Skill LinkExtends two-to-five-hit moves and triple kick to their full length every time.
OvercoatHAProtects against damage from weather.

Getting Cloyster requires an evolution item, not just grinding levels. The chain starts at Shellder. Breed this form to get Shellder eggs (average hatch time). Defense grew the most through evolution (+80 over Shellder), and Cloyster peaks at 525 total stats.

How to Evolve

2 Forms
Shellder
#090Shellder
Water Stone
Cloyster
#091Cloyster
Stat Comparison 2 Stages
Shellder
Water
Cloyster
WaterIce
HP
30
50+20
ATK
65
95+30
DEF
100
180+80
SP.ATK
45
85+40
SP.DEF
25
45+20
SPE
40
70+30
BST
305B-Tier
525B-Tier+220
ROLE
Balanced
Balanced
TYPE
Physical
Mixed
Breeding
Very Easy

Breed with Cloyster to get Shellder eggs easily using 19 partners from the Water3 egg group. Notable egg moves include Barrier, Bubble Beam, Icicle Spear and 3 more.

Egg Groups
Water3
Gender
♂50.0%♀50.0%
Hatch Time
20 cycles·5,140 steps
Quick~5 min with Flame Body
Egg Moves
6moves
Breed With (best first)
crawdauntcorsolacorphishomastarkabutopsomanytekabutotentacruelcloysterstarmiekinglerstaryu
12 of 19·

This build takes hits and hits back. Leftovers provides passive recovery each turn, Shellarmor supports the gameplan, and a spread EV build EVs mean Cloyster doesn't crumble to chip damage. Plus Normal coverage backing it up.

Best Build

Hazard Setter
Ability
Shellarmor
Item
LeftoversSUSTAIN
Nature
Timid+SPE
EVs

Best Cloyster Moveset

  • SpikesHazard
  • ExplosionCoverage
  • SurfSTAB
  • Rapid Spin

Recommended Teammates

Tyranitar
TyranitarDecent
Gengar
GengarDecent
Metagross
MetagrossDecent

You'll want to breed for Barrier and Bubble Beam on Cloyster. These egg moves aren't just nice to have. Combined with STAB from Blizzard and Ice Beam, they expand what Cloyster can actually threaten in practice.

Level-Up Moves

Lv 1
Aurora Beam
6510020Ice
Lv 1
Protect+4
——10Normal
Lv 1
Supersonic
—5520Normal
Lv 1
Withdraw
——40Water
Lv 36
Spikes
——20Ground
Lv 43
Spike Cannon
2010015Normal

TM Moves

Src
TM45
Attract
—10015Normal
TM14
Blizzard
120705Ice
TM
Dive
6010010Water
TM32
Double Team
——15Normal
TM42
Facade
7010020Normal
TM21
Frustration
—10020Normal
TM07
Hail
——10Ice
TM10
Hidden Power
6010015Normal
TM15
Hyper Beam
150905Normal
TM13
Ice Beam
9510010Ice
TM17
Protect+4
——10Normal
TM18
Rain Dance
——5Water
TM44
Rest
——10Psychic
TM27
Return
—10020Normal
TM43
Secret Power
7010020Normal
HM03
Surf
9510015Water
TM41
Torment
—10015Dark
TM06
Toxic
—8510Poison
TM03
Water Pulse
6010020Water

Egg Moves

Src
Egg
Barrier
——30Psychic
Egg
Bubble Beam
6510020Water
Egg
Icicle Spear
2510030Ice
Egg
Rapid Spin
5010040Normal
Egg
Screech
—8540Normal
Egg
Take Down
908520Normal

Tutor Moves

Src
Tutor
Double-Edge
12010015Normal
Tutor
Explosion
2501005Normal
Tutor
Mimic
——10Normal
Tutor
Substitute
——10Normal

Reminder Moves

Src
Rem
Clamp
358510Water
Rem
Ice Beam
9510010Ice
Rem
Icicle Spear
2510030Ice
Rem
Leer
—10030Normal
Rem
Tackle
3510035Normal

No wild encounters for Cloyster. The 2-stage line runs through Shellder, which you can catch at solid rates from the locations below. Evolve through a special method once you've got the levels.

How to Obtain Cloyster in FireRed & LeafGreen

The path to Cloyster starts with Shellder at Lv. 15-25 via fishing encounters. 1 catchable stage total, with locations listed for each one below.

  1. Shellder
    Step 1Catch Shellder
    Cinnabar Island
    Super RodLv.15-25CommonEarlyWater
    EASY
    Five Island
    Super RodLv.15-25CommonEarlyWater
    EASY
    Icefall Cave - 1F Room 3
    Super RodLv.15-25CommonEarlyCave
    EASY
    One Island
    Super RodLv.15-25CommonEarlyWater
    EASY
    Pallet Town
    Super RodLv.15-25CommonEarlyCity
    EASY
    Vermilion City - City
    Super RodLv.15-25CommonEarlyCity
    EASY
    Vermilion City - Harbor
    Super RodLv.15-25CommonEarlyCity
    EASY
  2. Cloyster
    Step 2Cloyster ✓

  • We rate Cloyster B-Tier — a solid choice for the right team. At 525 BST, it fits the hazard setter role. Base 180 Defense stands out.

  • Watch for Raikou (Electric), Venusaur (Grass), and Hitmonlee (Fighting) when using Cloyster. They all hit it super-effectively with STAB. Rock-type attackers are also a problem.

  • Shellder evolves into Cloyster using a Water Stone. Cloyster is the fully evolved form. At 525 BST, it's got solid stats to work with.

  • Shell Armor protects against critical hits — that's the one you want on Cloyster. Overcoat is the hidden ability. Niche, but it has its uses. Skill Link works too if your team needs something different.

  • Base 70 Speed is workable — faster than some, slower than many. On offense, Cloyster is a mixed attacker — base 95 Attack and 85 Sp. Atk. Defensively? Enough bulk to take a hit or two. Best used as a hazard setter.

  • Cloyster appears in 20 games, including Yellow, Red & Blue, and Gold & Silver.

One of the original 151, Cloyster has appeared in 20 games — nearly every mainline game. From Red & Blue through the latest titles, it's rarely been left out of a regional Pokedex.