Hi Gabe! Thanks for dropping by planDisney.
Guests currently need both a valid admission ticket and theme park reservation to enter the parks, and as you've encountered, theme park reservations can fill up on popular days. With
Park Hopper, you're selecting the park you'd like to start your day in. You'd start your day in Disneyland Park, which still has
availability for your preferred park day, and then later, you would hop to Disney California Adventure Park. While there are no remaining theme park reservations for Disney California Adventure Park, you don't need a reservation for your second park with Park Hopper. It is possible for a park to briefly reach capacity and limit the entrance of Guests, but this is an extremely rare event with the advent of theme park reservations, and if it does happen, it is temporary. I wouldn't worry about the prospect!
So, your answer is yes, you can upgrade to Park Hopper, which will allow you to start your day in Disneyland Park and then hop over to Disney California Adventure Park. You'll have to pay the difference for this upgrade. Prices and terms are subject to change. I can walk you through how to go about upgrading.
Quickly check if there's an upgrade link on your admission tickets in the
Disneyland mobile app. There's a "My Tickets & Passes" tile under the three-bar menu at the bottom right side of the app that takes you to your tickets. You should be able to swipe through all the tickets linked to your account. Look for the upgrade or modify link below your tickets. If it's not there, you'll want to call the
Tickets phone line. A helpful Cast Member can assist you with the upgrade. Have a method of payment handy before you call to facilitate the speed of your transaction. I called over there the other day and only had to wait a couple of minutes. Hopefully, the whole thing will be just as quick for you! Let them know you have an existing park reservation.
I hope you're able to upgrade and enjoy both parks! Check out the Disney California Adventure Food & Wine Festival if you get a chance. I recommend the Cheeseburger Bao from the California Craft Brews festival booth. It's delicious. My kids agreed too.
Have a magical day.
Elizabeth