Hello, Randy! Thanks for bringing your question to planDisney!
I love park hopping at the Disneyland Resort! With Disneyland Park and Disney California Adventure Park mere steps away from each other, park hopping could not be easier. Plus I like the flexibility that having a
Park Hopper ticket allows. You can most certainly upgrade your one park per day tickets to Park Hopper tickets. To do this, you will need to stop by a ticket booth when you arrive at the Disneyland Resort. Keep in mind, though, that adding the Park Hopper option is a flat fee per ticket, not per day. So it will be the same price to add it to all three days as it would be to only add it on your last day. I suggest stopping by the ticket booth on your first day so you can have the option of park hopping during all three days of your trip.
If you haven't purchased your theme park tickets yet, you can add the Park Hopper option at the time of purchase online so you don't have to stop by a ticket booth at all. You will need to make
theme park reservations for each day you want to visit the parks. If you buy your tickets on the Disneyland Resort website, you will choose your dates and which park you want to start at each day before you check out. With Park Hopper tickets, you will make a reservation for the park you want to start at each day and then at 1:00 p.m., you can hop to the other park.
I hope this information was helpful. Have a terrific time at the Happiest Place on Earth!
-Linda