Mixed
Balanced
525High
70Moderate
ATier

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
Catch60ChallengingSlow1.25M XP1.5m / 4'11"132.5kg / 292.1 lbs184Base XP
Pokedex Entries

For protection, it uses its harder-than-diamonds shell. It also shoots spikes from the shell.

Yellow

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 I Type Chart
  • Only 15 types exist — Dark, Steel, and Fairy are absent
  • Ghost has no effect on Psychic (a known bug, fixed in Gen II)
  • Special stat governs both offense and defense — no Sp.Atk / Sp.Def split
4xCriticali
None
½xResisti
¼xResisti
0xImmunei
None
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.

The Water/Ice-type Cloyster caps Shellder's chain at 525 stats. No daycare options for this one. Defense grew the most through evolution (+80 over Shellder), and Cloyster peaks at 525 total stats.

How to Evolve

2 Forms
Stat Comparison 2 Stages
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 not available · Introduced in Gen 2

an item and an ability form the backbone. Cloyster invests flexible EVs EVs to play its attacker role properly, and a nature nature pushes higher. Clamp handles the heavy lifting on offense. Normal coverage rounds it out.

Best Build

Utility
Ability
Not in Gen 1
Item
Not in Gen 1
Nature
Not in Gen 1

Best Cloyster Moveset

  • ExplosionCoverage
  • ClampSTAB
  • BlizzardSTAB
  • RestRecovery

Level-up moves are just the starting point for Cloyster. TMs unlock Normal coverage and turn a straightforward STAB kit around Blizzard and Ice Beam into something with actual range.

Level-Up Moves

Lv 1
Aurora Beam
6510020Ice
Lv 1
Clamp
358510Water
Lv 1
Supersonic
5520Normal
Lv 1
Withdraw
40Water
Lv 50
Spike Cannon
2010015Normal

TM Moves

Src
TM34
Bide+1
10Normal
TM14
Blizzard
110905Ice
TM11
Bubble Beam
6510020Water
TM32
Double Team
15Normal
TM10
Double-Edge
12010015Normal
TM47
Explosion
2501005Normal
TM15
Hyper Beam
150905Normal
TM13
Ice Beam
9510010Ice
TM31
Mimic
10Normal
TM20
Rage
2010020Normal
TM33
Reflect
20Psychic
TM44
Rest
10Psychic
TM36
Self-Destruct
2001005Normal
TM50
Substitute
10Normal
HM03
Surf
9510015Water
TM39
Swift
6020Normal
TM09
Take Down
908520Normal
TM30
Teleport-6
20Psychic
TM06
Toxic
9010Poison
TM49
Tri Attack
8010010Normal
TM12
Water Gun
4010025Water

Egg Moves

Cloyster doesn't have any Egg moves

Tutor Moves

Cloyster can't learn any Tutor moves

Reminder Moves

Src
Rem
Ice Beam
9510010Ice
Rem
Leer
10030Normal
Rem
Tackle
3510035Normal

Can't catch Cloyster directly. Start with Shellder at solid rates from the locations below, then evolve through a special method. The 2-stage line from Shellder to Cloyster is where the leveling time goes.

How to Obtain Cloyster in Yellow

Shellder is your first catch on the way to Cloyster. You'll find fishing encounters from Lv. 10-40 across 3 total spots in the chain.

  1. Shellder
    Step 1Catch Shellder
    Vermilion City - Harbor
    Super RodLv.10UncommonEarlyCity
    MODERATE
    Route 18
    Super RodLv.20-40CommonMidRoute
    EASY
    Route 17
    Super RodLv.25-35CommonMidRoute
    EASY
  2. Cloyster
    Step 2Cloyster
  • We rate Cloyster A-Tier — a strong competitive pick. At 525 BST, the stats are spread pretty evenly. 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.

  • 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.

  • 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.