Hey Elizabeth!
Thanks for bringing your question to planDisney!
The Park Hopper option on a multi-day
Disneyland Resort theme park ticket applies to all days on the
ticket. There is no option to add the Park Hopper option on only a single day. So, if you decide you would like to upgrade, you’ll be paying for the upgrade for all 5 days. Please note that the request to add the Park Hopper option must be made in person at the Disneyland Resort Main Entrance Ticket Booth and it is subject to availability.
Park Hopper tickets give you the option to hop to the other theme park starting at 11:00 a.m. each day of your visit. You’re not required to make another
Theme Park Reservation to visit the other park and you may hop back and forth as often as you like. But, as always, theme park admission is subject to attendance availability.
Thanks again for your question! If you have any more, bring them our way.
Tiffanie