Postgame · Unknown Dungeon
Pokemon Yellow Cerulean Cave
After you become Champion, Cerulean Cave opens. Navigate 1F → 2F → B1F, loot Ultra Balls and Max heals, then face optional Mewtwo (Lv.70, CR 3). Track the route, catch odds, and every pickup below.
Fast answer
Champion → B1F → Lv.70 Mewtwo
Clear the Elite Four and Champion. Enter Cerulean Cave from northwest Cerulean City, work through 1F/2F ladders to the B1F warp, then save in front of Mewtwo. Use the Master Ball (Silph Co. 11F) or status + Ultra Balls (catch rate 3).
Postgame gate
Blocked until you are Champion
The cave entrance stays closed during the main story. If a guide sends you to Mewtwo mid-run, ignore it—Yellow only unlocks Cerulean Cave after the Hall of Fame. Birds (Articuno, Zapdos, Moltres) can be caught earlier.
Interactive tool
Cave route tracker
Mark each stage done. Map pins match the Yellow Cerulean Cave layout.
Master Ball first choice
Silph Co. 11F awards the only guaranteed Master Ball in a normal playthrough. Saving it for Mewtwo is the classic plan.
Max Repel spam
Wilds run Lv.50–65. Max Repels cut random battles while you ladder between floors hunting the B1F warp.
Loot Ultra Balls en route
Four+ Ultra Balls sit as visible pickups across floors—grab them before the fight if you spent the Master Ball earlier.
Recover risk
Mewtwo can Recover. Chip carefully and keep a strong special attacker ready if the fight turns into a stall.
Gates
Requirements
Hall of Fame
Defeat Lorelei, Bruno, Agatha, Lance, and the Champion Rival. The cave guard requirement is Champion status.
Surf + balls
Surf helps on water tiles inside the cave. Bring Master Ball or a deep Ultra Ball stack plus sleep/freeze.
Legendary
Mewtwo catch tool
Cerulean Cave B1F static
Its generated Lv.70 moves are Swift, Psychic, Barrier, Recover. Ghost attacks do no damage to Psychic in Yellow, so use strong physical neutral damage and reliable status instead. Save first—one battle per save if KO’d.
Default Max HP ≈240 is a mid-DV estimate for Lv.70 Mewtwo (base 106 HP). Adjust if your calc differs. Formula matches the site Catch Planner. Master Ball defaults to 100%.
Status priority
Sleep or freeze (+25) beats paralysis/poison/burn. False Swipe is not in Yellow—chip with weak moves and watch Recover.
Not Mew
There is no static Mew in Cerulean Cave. Mew requires the glitch methods (or external events)—see the Mew glitch guide.
Pickups
Cerulean Cave items
| Item | Location | Kind | Note | Links |
|---|
Wilds
Cerulean Cave encounters
| Pokémon | Levels | Floors | Methods |
|---|
B1F Chansey and high-level Ditto are popular postgame hunts alongside Mewtwo.
Tips
Clear faster
Heal in Cerulean
No center inside the cave. Heal, deposit, and restock before every deep push toward B1F.
Birds first, Mewtwo last
Zapdos, Articuno, and Moltres are available before the League. Mewtwo is the postgame crown.
Bug bite Psychic
Bug is super effective against Psychic in the type chart, but Yellow’s Pinsir and Scyther are obtainable without trade and have no damaging Bug STAB in their level/TM pools. Use their strong neutral physical moves, or choose another reliable physical attacker.
My Run flag
Track Champion + Mewtwo in My Run so you do not re-walk empty floors after a successful catch.
Checklist
Cerulean Cave completion
FAQ
Mewtwo & Cerulean Cave questions
How do I catch Mewtwo in Pokemon Yellow?
Become Champion, enter Cerulean Cave, reach B1F, save, then Master Ball or sleep/freeze + Ultra Balls on the Lv.70 static.
What level is Mewtwo?
Level 70 with catch rate 3 on Cerulean Cave B1F.
Why can’t I enter Cerulean Cave?
It opens only after the Hall of Fame. Finish the Elite Four and Champion first.
Where is the Master Ball?
Silph Co. 11F from the President after the Giovanni story battle during Silph Co.
Is Mew in Cerulean Cave?
No. Only Mewtwo is the static legendary here. Mew needs glitch methods.
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