Hi Deborah and welcome to the Disney Parks Moms Panel.
From reading your question, I am assuming that you travelling from the UK and have purchased Disney's 14-Day
Ultimate Tickets.
If you wish to visit a Disney Theme Park on both your arrival and departure day, your only real option would be to purchase a 1-Day Theme Park Ticket to cover either your arrival or departure day.
The price of a 1-Day Theme Park ticket varies depending on which Theme Park you will be visiting and the date of your visit. The
Theme Park Ticket section of the Walt Disney World website (English (USA) version) will provide you with more information on 1-Day Theme Park Tickets.
To get around this issue, my family normally plan to visit
Disney Springs on our day of departure to do some last minute shopping, before flying back to the UK.
Wishing you a magical trip filled with memories which will last a lifetime!
Emma