Hi Lynthia,
Welcome to planDisney! Ohmygoodness...I see that your
Disneyland Resort adventure begins TOMORROW! I bet you're practically
bursting with excitement and anticipation! Just think of all the magic and fun you'll be enjoying this time tomorrow! HOORAY!
While subject to change, it currently costs $55 to upgrade your
ticket to a Park Hopper ticket. That cost remains the same whether you have a 1-day ticket or a 5-day ticket, so if you'll be visiting for multiple days, the earlier you upgrade, the better! All you'll need to do is swing by a ticketing booth and pay the difference between the ticket you currently have and the one to which you'd like to upgrade.
Park-hopping privileges are subject to any capacity limitations, so if you're only visiting for one day, you may want to confirm that there is park-hopping availability before you pay to upgrade. You're exactly right, though, that the park-hopping window opens each day at 1:00 PM. With
Disneyland Park and
Disney California Adventure Park only steps away from each other, upgrading to a Park Hopper ticket sounds like a
fantastic plan to me!
Thanks so much for bringing your question to us here at planDisney, Lynthia. I'm sending pixie dust that you have a truly magical vacation and make memories to cherish for years to come!
Missy