The Stadium is arguably Pokémon Stadium's main mode. Here, you can enter your Pokémon to compete in four cup tournaments with four differet sets of rules.

Pika Cup (Level 15-20) A Cup tournament open to the lowest-level Pokémon.

Petit Cup (Level 25-30) Open to smaller Pokémon between the levels of 25 and 30.

Poké Cup (Level 50-55) The official Pokémon League tournament for high-level Pokémon.

Prime Cup (Level 1-100) The ultimate tournament without level restrictions.

Once you have beaten all four tournaments as well as the Gym Leader Castle, a bonus tournament will open up: VS Mewtwo. Six of your Pokémon compete against the dangerous clone. When you have beaten all the Cups, Gym Leader Castle and Mewtwo, a new mode called R-2 will appear. The rules are the same, but all the Pokemon have changed.

The Pika and Petit Cup are really tailor-made for beginners as they don't last too long and the computer only uses lower-level Pokémon with weak attacks. Each one of these cups is made up of eight separate battles against eight different trainers. Whenever you beat a trainer, you receive a badge (Boulder, Cascade, Thunder, Rainbow, Soul, Marsh, Volcano, or Earth). Once you beat the last trainer, you've won the cup. Sounds easy, right? Well, once you get to the Poké and Prime cups, you'll quickly realize that it takes quite a while to get through since both of these cups are further divided into four subdivisions. In order to completely beat the Poké and the Prime cups, you have to battle yourself from the Poké Ball division all the way up to the Master Ball division -- and defeat all eight trainers in each one. In the Prime Cup, the lowest level of your opponent's Pokémon will be equal to your highest Pokémon level. This should be enough incentive for you to keep the levels of your six contestants as closely together as possible. You start with zero continues, but if you score a perfect win – meaning none of your Pokémon faint during battle – you'll earn a continue that lets you retry a battle in case you lose. If you lose and you're out of continues, you have to restart from the first badge in the tournament. Not fun. Luckily, there are some additional rules that keep the battles from getting boring (ie too long). For example, no two Pokémon can be frozen or asleep at the same time, you can't use a self-destruct technique with the last Pokémon, and so on. The rest of the mode is similar to the Gym Leader mode. You select three out of six Pokémon and battle it out against the computer. As with all of Pokémon Stadium's modes, items can't be used at all.