Hidden Grottoes Guide - All 22 Locations, Pokémon & Items
Hidden Grottoes are special locations where you can find rare Pokémon with Hidden Abilities and valuable items. This guide covers all grotto locations & their contents!
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!
These grottoes were inspired by the Hidden Grotto feature from Pokémon Black 2 and White 2 (Generation V), but adapted to fit the Pokémon Polished Crystal experience and carefully curated encounter lists!
Why Hidden Grottoes Matter in Polished Crystal
Hidden Grottoes are one of the most important optional systems in Polished Crystal because they provide early and repeatable access to Hidden Abilities, which can dramatically change how certain Pokémon perform in battle.
For players building optimized teams, Hidden Grottoes offer:
- Earlier access to competitive abilities
- Pokémon that scale to your current progression
- High-value items without relying on RNG-heavy methods
Ignoring Hidden Grottoes often means missing out on some of the strongest utility and synergy options in the game.
Optimal Hidden Grotto Strategy
To get the most value from Hidden Grottoes:
- Check grottoes after earning a new badge, when level scaling improves
- Prioritize grottoes with high-impact Hidden Abilities early (e.g., weather, immunity, or stat-boosting abilities)
- Bring the Itemfinder to avoid missing hidden item rolls
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:
Johto
Kanto
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
Best Hidden Grotto Targets
If you are hunting for team impact instead of completion, start with these:
| Target | Grotto | Hidden Ability | Why It Matters |
|---|---|---|---|
Route 36 | Drought | Enables sun teams early, boosting Fire moves and supporting Chlorophyll partners. | |
Ruins of Alph | Magic Bounce | Reflects many status and hazard-style support moves, and can become a Magic Bounce Xatu. | |
Route 44 | Regenerator | Becomes a strong pivot that heals when switching out. | |
Route 44 / Route 45 | Immunity | Avoids poison, which makes long routes and defensive play much safer. | |
Route 35 Coast | Sap Sipper | Turns Grass moves into free Attack boosts. | |
Route 35 Coast | Sheer Force | Gives Tauros a much more threatening offensive profile. | |
Yellow Forest | Lightning Rod | Gives teams an Electric immunity option and protects teammates weak to Electric moves. | |
Bellchime Trail | Anticipation | Can evolve into Hidden Ability Eeveelutions, including Magic Bounce Espeon. |
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.
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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):
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.
| Team style | Grotto targets | Why it works |
|---|---|---|
Sun offense | Drought Vulpix, Harvest Exeggcute, Chlorophyll partners from outside grottoes | Drought gives Fire attacks immediate pressure and lets sun-focused Grass types snowball faster. |
Sand balance | Sand Stream Dunsparce, Sand Veil Graveler/Donphan, Sand Force Steelix | Sand gives chip damage while several grotto Pokémon either benefit from or tolerate the weather. |
Bulky pivoting | Regenerator Tangela/Corsola, Magic Bounce Natu/Eevee, Immunity Gligar | These picks help you switch more safely, shrug off status pressure, and keep momentum across longer fights. |
Offensive utility | Sheer Force Tauros, Skill Link Aipom, Defiant Mankey/Farfetch'd | These are good targets when you want a Pokémon that immediately changes damage output or punishes stat drops. |
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:
- Start in Johto - Check early-game grottoes first
- Use Fly - Minimize travel time between locations
- Bring Itemfinder - Don't miss hidden items (40% of spawns)
- Save before interaction - Soft reset if you want a different nature/IVs
Targeting Specific Pokémon
- Identify your target grotto from the list above
- Soft reset until the desired Pokémon spawns (20% chance for any Pokémon, then rarity within that)
- Save before catching if you want to reset for nature/IVs
- Catch at appropriate level - Higher badges = higher levels = less training needed
Nature Hunting
Hidden Grotto Pokémon have random natures. For competitive Pokémon:
- Save before entering the grotto area
- Check if a Pokémon spawned (20% chance)
- Check the nature in battle
- Soft reset if nature is unfavorable
- 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.asmlines 241-263 - Grotto data table:
polishedcrystal/data/events/hidden_grottoes/grottoes.asmlines 1-165 - Initialization logic:
polishedcrystal/engine/events/hidden_grottoes.asmlines 15-93
Spawn Probabilities
- Content type distribution (20/40/40):
polishedcrystal/engine/events/hidden_grottoes.asmlines 36-44 - Pokémon selection rates (37.5/37.5/20/5):
polishedcrystal/data/events/hidden_grottoes/probabilities.asmlines 1-6 - Item probability tables:
polishedcrystal/data/events/hidden_grottoes/probabilities.asmlines 8-30
Daily Reset
- Grotto reset function:
polishedcrystal/engine/events/hidden_grottoes.asmlines 114-124 - Daily flag system:
polishedcrystal/engine/overworld/time.asmlines 129-141 - Daily flags definition:
polishedcrystal/data/events/engine_flags.asmline 151
Hidden Abilities
- Grotto Hidden Ability guarantee:
polishedcrystal/engine/pokemon/move_mon.asmlines 236-238 - Normal wild Hidden Ability rate (5%):
polishedcrystal/engine/pokemon/move_mon.asmlines 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.asmlines 3-18
Special Mechanics
- First grotto Pokémon guarantee:
polishedcrystal/engine/events/hidden_grottoes.asmlines 31-32 - Shiny exclusion:
polishedcrystal/engine/pokemon/move_mon.asmlines 267-268 - Grotto empty flag:
polishedcrystal/engine/events/hidden_grottoes.asmlines 126-129
Data Extraction
- Extraction script:
scripts/extract-grottoes.tslines 1-363 - Output manifest:
public/api/grottoes.json
- Nature GuideUse grotto Synchronize Pokémon for nature hunting
- Breeding GuideBreed grotto Pokémon to pass down Hidden Abilities
- Shiny Rates GuideNote: Grotto Pokémon cannot be shiny
- Ability Tier ListSee which Hidden Abilities are worth hunting
- IVs & EVs GuideTrain your grotto catches for competitive play
- Team Building BasicsBuild teams around powerful Hidden Abilities
- Wonder Trade GuideAlternative source for Hidden Ability Pokémon
- Evolution Items GuideSome grotto items help with evolutions
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