Hiya, Jennifer!
Welcome to planDisney! Thank you so much for sending this
Disneyland Resort vacation planning question to us hEAR!
Oh boy! I think this sounds like a wonderful plan. I'm always in support of some Disney days. This is a great question with an even better answer, Jennifer. Technically, yes, you could attempt to upgrade to the Park Hopper option for just your fourth park day. This can only be done on that last day, when you're actually in the parks, in person at the Ticket Booths between
Disneyland Park and
Disney California Adventure Park. (Double check your
Disneyland Mobile App on that last day as there might be an upgrade option there.)
However, if you
definitely know that you really do want the Park Hopper option, you'll be better off adding it to your
Theme Park Admission Tickets now, at the time of purchase, as the price of the add-on will cover
all four of your days, not just that one last day. (Plus it'll be one less line you'll need to stand in now vs. same-day!)
Bonus Tip: I'm not sure when you're planning your visit, but you can double-check the
Park Pass Reservation Availability Calendar hEAR before you buy your admission tickets. Each Guest needs to have a
Park Pass Reservation for each theme park day in addition to their tickets. Guests who have the Park Hopper option will notate which park they plan to play in first as their selection for that day. You'll then be welcome to hop between the two parks as much as you'd like starting at 1:00 P.M.
I hope that this helped to better plan your upcoming visit to Mickey's house, Jennifer! Be sure to follow the
official planDisney Panel Instagram account for even more tips and tricks. And if you have any more
Disneyland Resort vacation planning questions, We're All Ears!
~Kristen N.