Pokemon Stadium Cheat Codes & Secrets

Gym Leader Castle Rewards

Beating Gym Leader Castle in Round 1 earns you a free Level 5 starter Pokémon from Professor Oak — specifically whichever starter your rival didn’t choose. Complete it again in Round 2 (the harder post-game difficulty) to receive the second remaining starter. Finishing both rounds of Gym Leader Castle nets you all three Kanto starters without needing to trade from the Game Boy titles.

Unlocking Round 2

Round 2 — a significantly harder rematch mode where all opponents use fully optimized, high-level Pokémon — unlocks after you clear all four Stadium cups (Pika Cup, Petit Cup, Poké Cup, Prime Cup) and defeat the Gym Leader Castle gauntlet in Round 1. Every trainer in Round 2 carries different, stronger teams, rental pools are refreshed, and the AI plays more aggressively. This is considered the true challenge of the game.

Surfing Pikachu Unlock

One of the most famous secrets in the N64 library. To obtain a Pikachu that knows Surf:

1. In Pokémon Yellow, win the Surfing Pikachu mini-game at the Game Corner in Fuschia City (accessible only after specific conditions are met in that game).
2. Transfer that Yellow cartridge via the Transfer Pak to Pokémon Stadium.
3. The Pikachu with Surf is now accessible in battle and triggers a unique Surfing Pikachu animation during Stadium matches — the only Pikachu sprite in the game shown riding a wave.

Surfing Pikachu also unlocks a special trophy and contributes to 100% game completion.

Doduo and Dodrio Game Boy Tower Speeds

The Game Boy Tower (which lets you play your Red/Blue/Yellow cartridges on the N64 via the Transfer Pak) starts in standard Game Boy speed. You can upgrade it:

Dodrio mode makes grinding in the handheld games dramatically faster and is one of the most practical unlocks in the entire game for players also working through the Game Boy titles.

Prime Cup: Rental-Only Run Secret

Clearing the Prime Cup Master Ball division using only rental Pokémon (no transferred Pokémon from your cartridge) unlocks a special certificate and makes Amnesia Psyduck available as a rental in Free Battle mode. Amnesia Psyduck starts with the move Amnesia already learned — a move Psyduck cannot normally learn through level-up in Generation I — making it a novelty rental with boosted Special stat potential.

Kid’s Club Mini-Game Unlocks

Winning gold medals across all nine mini-games in the Kid’s Club arena unlocks an expanded Free Battle rental pool and grants access to a hidden trophy room viewable from the main menu. The nine mini-games include Clefairy Says, Run Rattata Run, Thundering Dynamo, Sushi-Go-Round, and others. Completing all nine on the hardest difficulty setting earns the full trophy display.

Mewtwo as a Rental Pokémon

Mewtwo is available as a rental Pokémon in Free Battle mode, but only after you clear the Prime Cup’s Master Ball division in Round 2. It does not appear in the rental pool until this condition is met. Once unlocked, Mewtwo is selectable in Free Battle only — you cannot use it in official cup competitions.

Beneficial Glitches and Exploits

Freeze glitch in Pika Cup: In the Pika Cup (where only Pokémon between Level 15–20 are legal), certain move combinations involving sleep-inducing moves applied to the opponent immediately before a round timer ends can cause the AI opponent to lock into a sub-optimal move loop on the following turn, repeatedly using a non-damaging move. This is inconsistent but has been reproduced on real hardware.

Rental stat variance: Rental Pokémon in Stadium use fixed stat values, but saving and reloading before a cup bracket resets which specific rentals appear in your pool. Players farming for a rental with a preferred moveset (such as a rental Starmie with Blizzard and Thunderbolt) would save before entering the rental screen and reset until the desired spread appeared. This is the closest thing to an RNG manipulation exploit in the game.

Transfer Pak save-state trick: When using the Game Boy Tower, the N64 does not write back to the cartridge save file until you explicitly exit the Tower. Players exploited this to duplicate items and Pokémon by entering the Tower, depositing items/Pokémon into the PC box system in the handheld game, then powering off the N64 before exiting — the deposited Pokémon or items would remain in the box on the cartridge while the originals were restored in the party. This requires a specific sequence and risks save corruption if timed incorrectly.

Stadium Mode Team-Building Shortcuts

Amnesia + Blizzard Slowbro rental strategy: In the Poké Cup, the rental Slowbro periodically appears with both Amnesia and Blizzard. Using Amnesia twice before the opponent can KO Slowbro effectively doubles the Special stat, making subsequent Blizzard hits powerful enough to one-shot most opponents in that cup tier. This is not a glitch but a legitimate rental optimization that experienced players documented early in the game’s life.

Type coverage exploit in Petit Cup: The Petit Cup restricts Pokémon to Levels 25–30 and excludes fully evolved forms. Haunter (not yet evolved to Gengar) is one of the strongest legal Pokémon in this bracket due to its Ghost/Poison typing and access to Night Shade, which deals fixed damage regardless of the level cap restrictions. Pairing Haunter with a Normal-type renders the opponent unable to hit one slot of your team with Normal moves at all.

Hidden Trophy Room

After unlocking all in-game trophies — earned through cup completions, mini-game medals, and the Surfing Pikachu unlock — a trophy room becomes viewable from the main hall screen. It serves no gameplay function beyond completion, but it was one of the earliest examples of collectible achievement displays on home consoles and a common goal for completionist runs of the game.