- "Oh, look out! By pressing the block button when the enemy attack is going to hit me, I can defend myself. But I have to get the timing just right so I really need to concentrate."
- —Polka, explaining about Guard
As an enemy attacks, the Guard option will be offered to the player, so long as the enemy does not attack from behind. Pressing the Guard button (Circle by default on PlayStation 3, B by default on Xbox 360) within the window of time presented will successfully Guard against the attack, mitigating most of the damage. Failure to Guard will result in the character taking the full brunt of the attack. Additionally, failure to Guard will often result in the character being unable to Guard against one or more subsequent attacks. Furthermore, since Guard only blocks a portion of the damage, the character can still be KOed if they were at low HP.
Many enemies also possess the ability to Guard against any attack targeted at them when the character directly faces their front. The various pirate enemies, as well as some bosses, have a high tendency to Guard against such attacks. The Dandelion opponent possesses the unique ability to Guard against any attack from any angle that does not hit for critical damage.
Beginning at Party Level 4, the player can sometimes Counterattack instead of Guard. This option is not always offered and when it is offered, the player can still choose to Guard instead by pressing the normal Guard button. If attempting a Counterattack, the player must time their move carefully, as a fail to Counterattack also counts as a failure to Guard and carries the same consequences.
At Party Level 6, the Guard button will rotate along with the buttons for Attack/Counterattack and Special Attacks when executing Harmony Chain. The player must take special care to pay attention to the current layout of the command buttons in order to avoid devastating failures to Guard.