The Memory Card 251 is a memory card which can be inserted into Slot A or B on the console. It allows settings and game status to be stored and game data (e.g. high score lists or game characters) to be exchanged to another Memory Card. To use this accessory, the game in question must support the Memory Card 251.

As a rule the Memory Card should be inserted into Slot A on the Nintendo GameCube. However, the console often recognises if the Memory Card is inserted into Slot B. Nevertheless the relevant instructions for the game in question should always be observed with regard to this.

The Memory Card should not be removed from the slot during the game as this can result in the loss of the stored data.

The memory capacity is divided into 251 blocks.