Polished Crystal Hidden Grottoes: All 22 Locations, Pokémon & Items

Introduction

Hidden Grottoes are special locations scattered throughout Johto and Kanto where you can find rare Pokémon with their Hidden Abilities and valuable items. Polished Crystal features 22 Hidden Grottoes, each with unique Pokémon encounters. Some locations will have Pokémon whose level will scale to your badges. You can check the individual tables below to see what would apply!

Quick answer

Hidden Grottoes are repeatable locations in Johto and Kanto that can contain a Pokémon, a visible item, or a hidden item. The first grotto you encounter guarantees a Pokémon; after that, check the grotto tables below for each location's encounters and item pool. For a specific evolution stone, use the Evolution Items guide, and use the Pokémon Pokédex to inspect each species.

Grotto Location Index

Use this index to find a specific Pokémon, rare item, or level rule. Each location can roll a Pokémon, a visible item, or a hidden item; the generated table below contains the complete encounter, ability, and item details.

For the full encounter rates, Hidden Abilities, screenshots, and generated item details, jump to the complete grotto display. To find a specific species, use the Pokémon Pokédex and then search this index for its grotto. For evolution stones, see the Evolution Items guide.

Why Hidden Grottoes Matter in Polished Crystal

Hidden Grottoes are optional, repeatable locations that provide Pokémon, items, and access to species with useful Hidden Abilities. The index above answers the location lookup first; the sections below explain the mechanics behind each result.

The tables are the source of truth for each grotto's encounters, levels, abilities, and item pool.

Hidden Grotto Strategy

To get more value from a grotto:

• Check badge-scaled grottoes after earning a new badge if you want higher encounter levels.
• Bring the Itemfinder so a hidden item roll is not missed.
• Use the location index and generated display to target a species or rare item instead of checking every grotto.

Because grottoes reset daily, you are also able to change the clock to farm for specific natures or IVs if desired. I would treat clock changes like a focused farming tool, not something to do casually: save first, know which daily events you have already collected, and remember that other time-based events can move along with the grotto reset.

Common Hidden Grotto Mistakes

• Ignoring grottoes early assuming they’re post-game content (My first run, oops)
• Skipping hidden item checks without the Itemfinder
• Farming before badge upgrades, resulting in weaker Pokémon (this isn't too much of a mistake as rather an inconvenience but still worth noting)
• Assuming every Pokémon has a Hidden Ability when some do not
• Assuming every Pokémon will hold an item

How Hidden Grottoes Work

Basic Mechanics

• Daily Reset: Hidden Grottoes reset once per in-game day (can be changed via the in-game clock system)
• Content Types: Each grotto can contain either a Pokémon, a visible item, or a hidden item
• One-Time Use: Once you interact with a grotto (catch the Pokémon or take the item), it becomes empty until the next daily reset
• Badge Scaling: Wild Pokémon levels scale with your badge count using the formula LEVEL_FROM_BADGES + N (where N varies by grotto)
• First Grotto Guarantee: The first Hidden Grotto you encounter always contains a Pokémon

Spawn Probabilities

While Pokémon encounters are the least common outcome, the guaranteed Pokémon in your first grotto ensures early exposure to the system. Over time, Hidden Items make up a significant portion of grotto value, especially for progression and post-game preparation.

When a grotto resets, it randomly determines what appears:

• 20% chance: Pokémon encounter
• 40% chance: Visible item
• 40% chance: Hidden item (Itemfinder is helpful here but you can probably find it without it too)

Hidden Abilities

All Pokémon encountered in Hidden Grottoes have their Hidden Ability. This is the primary reason to hunt in grottoes-many powerful Hidden Abilities are otherwise very difficult to obtain.

Examples of impactful Hidden Abilities include:

• Abilities that provide immunities or weather synergy
• Abilities that boost stats under common conditions
• Utility abilities that improve switching or survivability

Note: Every pokemon will have a defined hidden ability, but for some Pokémon it'll be less viable than one of their other ones, or it'll be the same as their other ones (but still appear as Ability H in the in-game stat screen)

Level Scaling

Grotto Pokémon levels match your current badge tier plus any grotto-specific modifier. The base badge levels are:

Badge-scaled grottoes use the base level for your current badge count, then apply the grotto's modifier. Fixed-level grottoes ignore badge count entirely.

Examples:

• Cherrygrove Bay: Badge +0, so 4 badges means Lv. 20 and 8 badges means Lv. 36
• Route 32 Coast: Badge +3, so 4 badges means Lv. 23 and 8 badges means Lv. 39
• Sinjoh Ruins: Badge +5, so 8 badges means Lv. 41 and 16 badges means Lv. 66
• Silver Cave: fixed Lv. 70, no matter how many badges you have

Notable Hidden Grotto Targets

These examples are linked to specific encounters in the generated data; they are not a ranking of the grottoes.

These are not the only good hunts, but they are the easiest to justify around actual battle roles: weather, immunity, pivoting, offensive boosts, and evolution lines with stronger Hidden Abilities.

All Grotto Locations

Each entry below lists the grotto screenshot, rare visible item, encounter level, all four Pokémon, rarity tier, encounter rate, and Hidden Ability. Use this as the full reference once you know which route or target you care about.

Route 32

Rare Item:

everstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	mareep	motordrive	common	37.5%	Lv. 5
	wooper	unaware	common	37.5%	Lv. 5
	ekans(johto)	unnerve	uncommon	20%	Lv. 5
	gastly	levitate(Non-Hidden)	rare	5%	Lv. 5

Ilex Forest

Rare Item:

leafstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	paras	damp	common	37.5%	Lv. 9
	oddish	runaway	common	37.5%	Lv. 9
	psyduck	swiftswim	uncommon	20%	Lv. 9
	pineco	overcoat	rare	5%	Lv. 9

Route 35

Rare Item:

sunstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	snubbull	rattled	common	37.5%	Lv. 15
	jigglypuff	soundproof	common	37.5%	Lv. 15
	yanma	frisk	uncommon	20%	Lv. 15
	ditto	imposter	rare	5%	Lv. 15

Route 36

Rare Item:

firestone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	stantler	sapsipper	common	37.5%	Lv. 16
	growlithe	justified	common	37.5%	Lv. 16
	vulpix	drought	uncommon	20%	Lv. 16
	houndour	unnerve	rare	5%	Lv. 16

Cherrygrove Bay

Rare Item:

shinystone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	exeggcute	harvest	common	37.5%	Badge +0
	skiploom	infiltrator	common	37.5%	Badge +0
	sunflora	earlybird	uncommon	20%	Badge +0
	corsola	regenerator	rare	5%	Badge +0

Violet Outskirts

Rare Item:

duskstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	rattata(alolan)	thickfat	common	37.5%	Badge +0
	bellsprout	gluttony	common	37.5%	Badge +0
	noctowl	tintedlens	uncommon	20%	Badge +0
	misdreavus	levitate(Non-Hidden)	rare	5%	Badge +0

Route 32 Coast

Rare Item:

waterstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	aipom	skilllink	common	37.5%	Badge +3
	weepinbell	gluttony	common	37.5%	Badge +3
	raticate	hustle	uncommon	20%	Badge +3
	arbok(johto)	unnerve	rare	5%	Badge +3

Stormy Beach

Rare Item:

waterstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	grimer(alolan)	corrosion	common	37.5%	Badge +3
	haunter	levitate(Non-Hidden)	common	37.5%	Badge +3
	golbat	infiltrator	uncommon	20%	Badge +3
	venomoth	wonderskin	rare	5%	Badge +3

Route 35 Coast

Rare Item:

thunderstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	miltank	sapsipper	common	37.5%	Badge +3
	tauros	sheerforce	common	37.5%	Badge +3
	magnemite	analytic	uncommon	20%	Badge +3
	voltorb	aftermath	rare	5%	Badge +3

Ruins Of Alph

Rare Item:

moonstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	sandshrew	sandrush	common	37.5%	Lv. 25
	natu	magicbounce	common	37.5%	Lv. 25
	quagsire	unaware	uncommon	20%	Lv. 25
	smeargle	moody	rare	5%	Lv. 25

Route 47

Rare Item:

shinystone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	farfetchd(galarian)	scrappy	common	37.5%	Badge +0
	cubone	battlearmor	common	37.5%	Badge +0
	machop	steadfast	uncommon	20%	Badge +0
	larvitar	sandveil	rare	5%	Badge +0

Yellow Forest

Rare Item:

thunderstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	ledyba	rattled	common	37.5%	Badge +0
	spinarak	sniper	common	37.5%	Badge +0
	meowth	unnerve	uncommon	20%	Badge +0
	pikachu	lightningrod	rare	5%	Badge +0

Rugged Road North

Rare Item:

firestone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	graveler	sandveil	common	37.5%	Badge +1
	growlithe(hisuian)	rockhead	common	37.5%	Badge +1
	skarmory	weakarmor	uncommon	20%	Badge +1
	dunsparce	sandstream	rare	5%	Badge +1

Snowtop Mountain Inside

Rare Item:

icestone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	swinub	thickfat	common	37.5%	Badge +4
	mrmime(galarian)	icebody	common	37.5%	Badge +4
	delibird	insomnia	uncommon	20%	Badge +4
	sneasel	pickpocket	rare	5%	Badge +4

Route 42

Rare Item:

duskstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	mankey	defiant	common	37.5%	Lv. 25
	marill	sapsipper	common	37.5%	Lv. 25
	machop	steadfast	uncommon	20%	Lv. 25
	graveler	sandveil	rare	5%	Lv. 25

Lake Of Rage

Rare Item:

waterstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	pidgeotto	bigpecks	common	37.5%	Lv. 26
	girafarig	sapsipper	common	37.5%	Lv. 26
	farfetchd	defiant	uncommon	20%	Lv. 26
	flaaffy	motordrive	rare	5%	Lv. 26

Bellchime Trail

Rare Item:

sunstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	sentret	frisk	common	37.5%	Lv. 20
	hoothoot	tintedlens	common	37.5%	Lv. 20
	magby	vitalspirit	uncommon	20%	Lv. 20
	eevee	anticipation	rare	5%	Lv. 20

Route 44

Rare Item:

leafstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	tangela	regenerator	common	37.5%	Lv. 34
	lickitung	cloudnine	common	37.5%	Lv. 34
	gligar	immunity	uncommon	20%	Lv. 34
	onix	weakarmor	rare	5%	Lv. 34

Route 45

Rare Item:

moonstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	donphan	sandveil	common	37.5%	Lv. 36
	ursaring	unnerve	common	37.5%	Lv. 36
	gligar	immunity	uncommon	20%	Lv. 36
	skarmory	weakarmor	rare	5%	Lv. 36

Route 46

Rare Item:

leafstone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	phanpy	sandveil	common	37.5%	Lv. 24
	teddiursa	honeygather	common	37.5%	Lv. 24
	zubat	infiltrator	uncommon	20%	Lv. 24
	dunsparce	sandstream	rare	5%	Lv. 24

Sinjoh Ruins

Rare Item:

icestone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	vulpix(alolan)	snowwarning	common	37.5%	Badge +5
	mrmime(galarian)	icebody	common	37.5%	Badge +5
	growlithe(hisuian)	rockhead	uncommon	20%	Badge +5
	sneasel(hisuian)	pickpocket	rare	5%	Badge +5

Silver Cave

Rare Item:

firestone

	Pokémon	Hidden Ability	Rarity	Rate	Level
	rapidash	flamebody	common	37.5%	Lv. 70
	sneasel	pickpocket	common	37.5%	Lv. 70
	steelix	sandforce	uncommon	20%	Lv. 70
	pupitar	battlearmor	rare	5%	Lv. 70

Pokémon Encounters

Encounter Rates

Each grotto contains exactly 4 Pokémon species with the following distribution:

• Pokémon 1: 37.5% (common)
• Pokémon 2: 37.5% (common)
• Pokémon 3: 20% (uncommon)
• Pokémon 4: 5% (rare)

When a grotto spawns a Pokémon (20% base chance), one of these four species is selected based on these probabilities.

Notable Hidden Ability Pokémon

Some particularly valuable Hidden Ability Pokémon available in grottoes:

Drought (sets sun):

• Vulpix - Found in Route 36, useful for Fire offense and sun-based support

Magic Bounce (reflects many status moves):

• Natu - Found in Ruins of Alph
• Eevee - Found in Bellchime Trail and can evolve into Magic Bounce Espeon

Regenerator (restores 1/3 HP when switching out):

• Tangela - Found in Route 44
• Corsola - Found in Cherrygrove Bay

Immunity (prevents poison):

• Gligar - Found in Route 44 and Route 45

Sheer Force (boosts many attacks by removing secondary effects):

• Tauros - Found in Route 35 Coast

Sand Stream (sets sandstorm):

• Dunsparce - Found in Rugged Road North and Route 46

Team Archetype Ideas

Hidden Grotto Pokémon are especially useful when you are building around a clear team identity instead of just catching one-off upgrades.

Ability and Item Combos Worth Chasing

• Drought Vulpix + Fire Stone: Route 36 can provide both the Hidden Ability Vulpix line and the Fire Stone needed to push it forward.
• Sap Sipper Miltank + Thunderstone hunting: Route 35 Coast is a strong stop because Miltank and Tauros are both practical catches, while the rare item slot can help with Electric-type evolutions.
• Regenerator Tangela + Leaf Stone: Route 44 is one of the best value grottoes if you like bulky Grass types, since Tangela is the headline catch and the rare item supports Grass evolution planning.
• Pickpocket Sneasel + Ice Stone routes: Snowtop Mountain Inside and Sinjoh Ruins are worth revisiting when you want Ice-type support and late-game item value from the same loop.

Item Drops

Visible Items (40% spawn rate)

When a grotto spawns a visible item, it selects from a weighted probability table including:

• Poké Balls (Great Ball, Ultra Ball)
• Potions (Super Potion, Hyper Potion)
• Repels (Super Repel, Max Repel)
• The grotto's unique rare item

Hidden Items (40% spawn rate)

When a grotto spawns a hidden item (requires Itemfinder), it selects from:

• Mulch (common)
• Mushrooms (Tiny Mushroom, Big Mushroom, Balm Mushroom)
• Leaves (Silver Leaf, Gold Leaf)
• Rare Candies
• PP items (PP Up, PP Max)

Using the Itemfinder

Hidden item rolls do not show a Poké Ball sprite, so a grotto can look empty even when it has value. If there is no Pokémon or visible item, stand near the center of the grotto and use the Itemfinder before leaving. This is especially important because hidden items are just as common as visible items.

The most common pitfall is checking only the entrance tile and leaving. Sweep the small grotto room before giving up: use the Itemfinder near the center, step around the open floor, and check again if the message suggests something is hidden nearby. If it says there is nothing hidden in the area, that grotto probably already had its daily content collected.

Rare Items

Each grotto has one unique "rare item" that can appear as part of its visible item pool. These include evolution stones and other valuable items specific to that location.

Hunting Strategies

Daily Grotto Route

Optimize your grotto hunting by planning an efficient route:

1. Start in Johto - Check early-game grottoes first
2. Use Fly - Minimize travel time between locations
3. Bring Itemfinder - Don't miss hidden items (40% of spawns)
4. Save before interaction - Soft reset if you want a different nature/IVs

Targeting Specific Pokémon

1. Identify your target grotto from the list above
2. Soft reset until the desired Pokémon spawns (20% chance for any Pokémon, then rarity within that)
3. Save before catching if you want to reset for nature/IVs
4. Catch at appropriate level - Higher badges = higher levels = less training needed

Nature Hunting

Hidden Grotto Pokémon have random natures. For competitive Pokémon:

1. Save before entering the grotto area
2. Check if a Pokémon spawned (20% chance)
3. Check the nature in battle
4. Soft reset if nature is unfavorable
5. Repeat until desired nature appears

Shiny Hunting

Note: Grotto Pokémon are explicitly excluded from shiny generation in the game code. Hidden Grotto encounters cannot be shiny.

Key Takeaways

• Hidden Grottoes reset once per in-game day and can contain a Pokémon, visible item, or hidden item.
• Grotto Pokémon always use their Hidden Ability slot, but some species' Hidden Ability may match a regular ability.
• Hidden items are common enough that the Itemfinder should be part of every grotto route.
• Badge-scaled grottoes become more convenient after major progression points, while fixed-level grottoes are good whenever you can reach them.
• Do not shiny hunt grotto Pokémon; the game code excludes them from shiny generation.

Troubleshooting FAQ

Why does a grotto look empty?

It may have rolled a hidden item. Use the Itemfinder before leaving. If nothing is found, you probably already collected that day's content.

Can I soft reset for a better nature or IVs?

Yes. Save before interacting with the grotto content, then reset if the Pokémon is not what you want.

Should I wait for more badges before catching something?

For badge-scaled grottoes, yes if you care about reducing training time. Fixed-level grottoes are unaffected by badges.

Why does the table say "Non-Hidden" next to some abilities?

Some Pokémon's Hidden Ability slot matches one of their regular abilities. They still come from the Hidden Ability slot in-game, but the ability itself may not be exclusive.

Can Hidden Grotto Pokémon be shiny?

No. The game explicitly excludes grotto encounters from shiny generation.

Do Hidden Grotto Pokémon hold items?

Do not plan around held items. The main item value of a grotto comes from visible item rolls, hidden item rolls, and each grotto's rare item pool.

Will this guide be updated?

Yes! The table is generated from the extracted grotto data, and the written guide gets updated when Polished Crystal changes mechanics or when we find better routing advice. If you notice a mismatch between your game and this page, please send it over with your version number and the grotto location.

Sources

All information in this guide is verified against the Polished Crystal source code:

Core Mechanics

• Grotto count (22 total): polishedcrystal/constants/script_constants.asm lines 241-263
• Grotto data table: polishedcrystal/data/events/hidden_grottoes/grottoes.asm lines 1-165
• Initialization logic: polishedcrystal/engine/events/hidden_grottoes.asm lines 15-93

Spawn Probabilities

• Content type distribution (20/40/40): polishedcrystal/engine/events/hidden_grottoes.asm lines 36-44
• Pokémon selection rates (37.5/37.5/20/5): polishedcrystal/data/events/hidden_grottoes/probabilities.asm lines 1-6
• Item probability tables: polishedcrystal/data/events/hidden_grottoes/probabilities.asm lines 8-30

Daily Reset

• Grotto reset function: polishedcrystal/engine/events/hidden_grottoes.asm lines 114-124
• Daily flag system: polishedcrystal/engine/overworld/time.asm lines 129-141
• Daily flags definition: polishedcrystal/data/events/engine_flags.asm line 151

Hidden Abilities

• Grotto Hidden Ability guarantee: polishedcrystal/engine/pokemon/move_mon.asm lines 236-238
• Normal wild Hidden Ability rate (5%): polishedcrystal/engine/pokemon/move_mon.asm lines 240-242

Level Scaling

• Badge-based level formula: polishedcrystal/data/events/hidden_grottoes/grottoes.asm (LEVEL_FROM_BADGES usage)
• Badge level table: polishedcrystal/data/wild/badge_base_levels.asm lines 3-18

Special Mechanics

• First grotto Pokémon guarantee: polishedcrystal/engine/events/hidden_grottoes.asm lines 31-32
• Shiny exclusion: polishedcrystal/engine/pokemon/move_mon.asm lines 267-268
• Grotto empty flag: polishedcrystal/engine/events/hidden_grottoes.asm lines 126-129

Data Extraction

• Extraction script: scripts/extract-grottoes.ts lines 1-363
• Output manifest: public/api/grottoes.json