Cerulean Cave and finding Mewtwo are the main objectives in Pokémon Let's Go's post-game, following on from your first battle with the Elite Four at Indigo Plateau.

Below, we'll cover any and all of the obtainable Pokémon, item locations, trainers and their squads that you might encounter in the area, as well as walking you through any key steps of the journey - like where each and every ladder leads - along the way.

We've also opted to break out walkthrough pages down into sections, referring to each of your visits to a given location, seeing as you often backtrack or revisit various places in your quest to become Champion! Where applicable, we'll split our page into one section for each visit, and of course if there are any, clearly mark any spoilers, too!

For more like this, be it specific systems explainers or walkthrough pages on more locations, head back to our main Pokémon Let's Go walkthrough and guide hub.

On this page:

Pokémon Let's Go: Cerulean Cave - how to find Mewtwo and how to beat it

Cerulean Cave, unlike the other caves of Pokémon Let's Go, only has one way in or out, so there's no fastest route to the other side for use to cover. Instead, your objective lies inside the cave itself: a showdown with the game's most powerful Pokémon, Mewtwo, and your chance to catch it.

It's relatively easy to reach Mewtwo, so here we'll detail how to do it step by step, whilst the sections below will cover the rest of Cerulean Cave and all the extremely rare items and Pokémon you can find here, which are well worth investigating!

pokemon_lets_go_cerulean_cave_1

The fastest way to find Mewtwo in Cerulean Cave

  1. Enter Cerulean Cave and go due north, across the water, to the first bit area you can land on in the north-east corner.
  2. Take the ladder there, 1F-A, up to 2F.
  3. On 2F, go all the way left (west) to the ladder we've labelled 2F-F, in the north-west corner, and take that back down to 1F.
  4. Back on 1F you'll be in a small corner area with another downwards ladder, 1F-G. Take that down to B1F.
  5. On B1F, head right (east) and then down (south), circling back on yourself to a body of water in the bottom left (south-west) corner of the room.
  6. Hop onto the water and surf north, to the western side of the room, where you'll find Mewtwo.

As with the other Legendary Pokémon - and other interactable Pokémon like the sleeping Snorlax you found earlier - you'll need to defeat Mewtwo in battle before you can catch it.

pokemon_lets_go_cerulean_cave_2

How to beat Mewtwo

This is by far your hardest challenge to date: Mewtwo is level 70, and boosts all of its stats when you first start the battle. It'll be faster than most of your Pokémon at a similar level, and deal out more damage than most, too.

The good news, however, is that Mewtwo only knows Psychic-type attacks. Dark-type Pokémon are totally immune to them, so any half-decent Dark-type that you have (there aren't many in Kanto: we used Mega-Gyarados, but you could also try Alolan Persian, Alolan Muk, or Alolan Raticate!). That'll allow you to sit there and take down it's health in total safety, as long as you remember to stay within the five-minute time limit!

pokemon_lets_go_cerulean_cave_3

If you don't have access to any Dark-types for whatever reason, another good tactic is using Paralysis. Thunder Wave and Stun Spore are reliable options, as is Eevee's Buzzy Buzz. Paralysis halves the Speed stat of the Pokémon affected, which'll make it much easier for you to get in big one-off attacks from your Pokémon before Mewtwo has a chance to attack and knock them out!

How to catch Mewtwo

Catching Mewtwo is also harder than it is with any other Pokémon, thanks to one difference: it has a force field, which goes up every now and then, that prevents you from using any items (in fact you can use items but they'd have no effect, so will go to waste!).

pokemon_lets_go_cerulean_cave_4

That means no berries for making it easier to catch - but it's easy enough to work around. Just get the Berry of choice ready to use and then wait for the force field to go down (it's the purple glowing aura around the Mewtwo), and quickly use it then. You can also use Balls at any time, they aren't affected by it, so if you're not using items, just crack on as usual! We have a dedicated guide to catching Pokémon in Let's Go if you're after some tips on perfecting your throws.

Pokémon Let's Go: Cerulean Cave Entrance 1F - available Pokémon, items and trainers

The rest of this page features sections on each of the three floors in Cerulean Cave, including where every ladder leads and all the available Pokémon, items and trainers as usual!

pokemon_lets_go_cerulean_cave_5

Cerulean Cave's hidden items

The main point of note here - outside of Mewtwo, of course - is that Cerulean Cave has an unusual item situation: it features a huge amount of rare items - all hidden - that respawn quite quickly, after just a few minutes (as opposed to the ususal one-day respawn rate for hidden items elsewhere in the world).

They also break down into three rough categories: the small number of hidden items that respawn in fixed areas on 1F and B1F, the large number of rare items that respawn at random in the glowing patches on 2F, and the small number of ultra-rare items (Fossils, Max Revives, and even Master Balls) that respawn at a slower rate in fixed locations on 2F and B1F. We note all of these in the tables within the sections below!

Quick tip: Your partner Pokémon's tail starts wagging when you're near a hidden item, and wags quickly when you're standing right by it. Use that to help sniff out all the hidden goodies!

Entrance Level 1F Ladders

ImageLadder LabelUp or DownLocationDestination
pokemon_lets_go_cerluean_cave_1fa
1F-A Up North-east corner on the small raised platform 2F-A
pokemon_lets_go_cerluean_cave_1fb
1F-B Up Central, on raised platform south of river 2F-B
pokemon_lets_go_cerluean_cave_1fc
1F-C Up Central, on smaller central platform south of river 2F-C
pokemon_lets_go_cerluean_cave_1fd
1F-D Up Central, on raised platform north of river 2F-D
pokemon_lets_go_cerluean_cave_1fe
1F-E Up South-west area on raised platform, near end of river 2F-E
pokemon_lets_go_cerluean_cave_1ff
1F-F Up North-east corner only accessible from 2F or B1F 2F-F
pokemon_lets_go_cerluean_cave_1fg
1F-G Down North-east corner only accessible from 2F or B1F B1F-A

Available Pokémon

PokémonNotes
Poliwag Water
Poliwhirl Water
Poliwrath Rare, Water
Magikarp Water
Geodude Standard walking
Graveler Standard walking
Lickitung Standard walking
Zubat Standard walking
Golbat Standard walking
Psyduck Standard walking
Golduck Standard walking
Rhyhorn Standard walking
Rhydon Standard walking
Ditto Standard walking
Snorlax Catch Combo

Available Items

ItemLocation
Full Heal At the end of the river, south side.
Max Revive In central raised up platform south of the river
Max Repel On raised upper platform in north-west area
PP Max North-east corner on the small raised platform by the ladder
Full Restore Hidden, in glowing patch in central raised platform south of the river
Rare Candy Hidden, on far west platform, facing upwards towards the little area with two ladders reached from 2F.

Pokémon Let's Go: Cerulean Cave Second Floor 2F - available Pokémon, items and trainers

This floor, 2F, is one open area with a large amount of ladders leading downwards, and a large amount of glowing patches, too. It also features one particular spot of interest.

pokemon_lets_go_cerulean_cave_6

That's the large glowing crystal in the centre of the room. It seems to have particularly rare items in it, with a random chance of you getting a Max Revive or any of the three fossils (Old Amber, Helix Fossil or Dome Fossil) and even a Master Ball, if you're lucky! It respawns every few minutes like the others.

2F Ladders

ImageLadder LabelUp or DownLocationDestination
pokemon_lets_go_cerluean_cave_2fa
2F-A Down North-east corner 1F-A
pokemon_lets_go_cerluean_cave_2fb
2F-B Down East of centre 1F-B
pokemon_lets_go_cerluean_cave_2fc
2F-C Down East of centre just left of 2F-B 1F-C
pokemon_lets_go_cerluean_cave_2fd
2F-D Down Central, along nothern wall 1F-D
pokemon_lets_go_cerluean_cave_2fe
2F-E Down South-west area of the room 1F-E
pokemon_lets_go_cerluean_cave_2ff
2F-F Down North-west corner 1F-F

Available Pokémon

PokémonNotes
Geodude Standard walking
Graveler Standard walking
Lickitung Standard walking
Zubat Standard walking
Golbat Standard walking
Rhyhorn Standard walking
Rhydon Standard walking
Ditto Standard walking
Chansey Standard walking
Snorlax Catch Combo

Available Items

ItemLocation
Max Lure Near the northern wall, fairly central
Full Restore Half way down eastern wall
Max Revive On the right of the small square block on eastern side
5x Ultra Balls Centre of the southern wall
Rare Candy South and and slightly west of centre, below a rectangular block
10x Ultra Balls Hidden, chance to find in glowing patch
Golden Razz Berry Hidden, chance to find in glowing patch
Golden Pinap Berry Hidden, chance to find in glowing patch
Ultra Ball Hidden, chance to find in glowing patch
Golden Nanab Berry Hidden, chance to find in glowing patch
Golden Nanab Berry Hidden, chance to find in glowing patch
Great Ball Hidden, chance to find in glowing patch
Ultra Ball Hidden, chance to find in glowing patch
Golden Pinap Berry Hidden, chance to find in glowing patch
Great Ball Hidden, chance to find in glowing patch
Dome Fossil Hidden, chance to find in large central crystal
Helix Fossil Hidden, chance to find in large central crystal
Old Amber Hidden, chance to find in large central crystal
Master Ball Hidden, chance to find in large central crystal

Pokémon Let's Go: Cerulean Cave Basement B1F - available Pokémon, items and trainers

The basement, B1F, has fewer items to find, but another spot like the large central cystal on 2F that has a chance of giving you a hidden Fossil or Max Revive.

pokemon_lets_go_cerulean_cave_7

Otherwise, this is where you'll find and battle Mewtwo (as explained in the top section) and, in a massive piece of fan service, battle the legendary Pokémon Trainer Green, too.

Green appears on the far left platform where you caught Mewtwo, once you've left and re-entered the cave having done so. She first throws Poké Balls at you, thinking you're a wild Pokémon yourself! After that she'll battle you, dissapointed that she lost out on the chance to catch the super-strong Pokémon.

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If you defeat her - she's one of the toughest trainers in the game - she'll reward you with the two Mewtwo Mega Stones: Mewtwonite X and Mewtwonite Y, which is the only way to get them!

Basement B1FLadders

ImageLadder LabelUp or DownLocationDestination
pokemon_lets_go_cerluean_cave_b1fa
B1F-A Up North-west area on raised platform 1F-G

Available Pokémon

PokémonNotes
Poliwag Water
Poliwhirl Water
Poliwrath Rare, Water
Magikarp Water
Geodude Standard walking
Graveler Standard walking
Lickitung Standard walking
Zubat Standard walking
Golbat Standard walking
Psyduck Standard walking
Golduck Standard walking
Rhyhorn Standard walking
Rhydon Standard walking
Ditto Standard walking
Snorlax Catch Combo
Mewtwo Defeat in battle.

Available Items

ItemLocation
Escape Rope In north-east corner
Full Restore Eastern end of central raised platform
Max Elixir South-west of central area just before the water
Dome Fossil Hidden, chance to find in little lower central ledge of central platform
Helix Fossil Hidden, chance to find in little lower central ledge of central platform
Old Amber Hidden, chance to find in little lower central ledge of central platform
Max Revive Hidden, chance to find in little lower central ledge of central platform
PP Max Hidden, in top left corner of water by Mewtwo's platform
5x Poké Balls On the floor after Green throws them at you
Mewtwonite X Defeat Green
Mewtwonite Y Defeat Green

Note that there's also another rare item respawning spot on this floor: above the small pool of water just right of the entrance ladder, on the left of that little area in the wall next to the large crystal. We haven't been able to prove if this is a Fossil-respawning spot or just a rare item spot, but will update if and when we do!

Trainers and Battles

Trainer NamePokémonLevel
Wild Mewtwo Mewtwo 70
Green Celfable
Ninetales
Victreebel
Kangaskhan
Gengar
Mega Blastoise
66
66
66
66
66
68

With that, you're done! Make sure you've cleared out the other optional area, the Power Plant, that's where you find Zapdos, but otherwise head back to our main Pokémon Let's Go walkthrough and guide hub for all the other pages we have like this, to check there's nothing else you've missed!

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About the author

Chris Tapsell

Chris Tapsell

Guides Writer

Chris Tapsell is Eurogamer's Guides Writer, its newest Chris, and a keen explorer of the dark arts of gaming, from League of Legends to the murky world of competitive Pokémon.

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