Hello Harriet!
Welcome to planDisney! December is a delightful time to visit and I'm glad that you are trying to make time to visit the most Magical Place on Earth!
Unfortunately, there are no afternoon-only or partial-day tickets available. When you arrive stateside you will only find single full-day option tickets to purchase. If you were to look while in Great Britain the shortest ticket option available is the
7-Day Magic Ticket. If you are only arriving for one afternoon I would recommend purchasing a single-day ticket once you arrive and consider adding on
Genie+ that morning. Genie+ can sell out but become available at midnight on the day of your visit. Starting from 7 AM you can, through the My Disney Experience Mobile App, make Lightning Lane return times. You can refresh a few times and modify bookings till you have them set up nicely for the afternoon. That way when you arrive for the afternoon and able to enjoy so many attractions with minimal wait. It's a great way to make use of your limited time. Don't forget that
Theme Park Reservations are still needed through January 8, 2024, even if you are only coming for the afternoon!
On the other hand, coming to the Parks for a relaxing afternoon of experiences and shows sounds perfect as well. Imagine yourself arriving at Magic Kingdom Park in time for the noon
Disney Festival of Fantasy Parade and then enjoying the classic
Walt Disney's Carousel of Progress which usually has a very little wait time. Then meander on your way through Main Street, U.S.A. to take a ride on the
Walt Disney World Railroad. I love the updates and surprises that are now included. Ok maybe, just maybe, I'm planning the perfect day for me but I'm sure you two will find your perfect day!
I hope this helps and I'm sorry I don't have better news for you but please still try and visit! If you have any more questions we are here to help!
Happy Planning!
-Nimmy