Yes, you can absolutely leave and re-enter Disneyland Park or Disney California Adventure on the same day, provided you have a valid theme park ticket and a corresponding reservation (if required by your ticket type). Re-entry is a standard feature that allows guests to take a "mid-day break" to nap at their hotel, have a cheaper meal in Downtown Disney, or avoid the peak heat of the afternoon. To re-enter, you simply scan your ticket at the front gate again; your photo, which was taken upon your first entry, is linked to your digital ticket in the Disneyland app, so no physical hand-stamp is required in 2026. This policy is particularly popular for families staying at on-property hotels like the Pixar Place Hotel or Disney's Grand Californian, as it makes transitioning between the park and the room seamless. Just be aware that if the park reaches maximum capacity (which is rare but can happen on peak holidays like New Year's Eve), re-entry is not guaranteed, so it's always wise to check the app for any capacity alerts before you head out for your break.