yes. If you book online, you just scroll down to the dining, click it & check which one you want to add. If you want the options on tickets (it gives 7 day base ticket) you can click on the tickets options & add hoppers and/or water parks & more too. If you're booking on the phone with Disney or your
travel agent, just tell them what you want to add.
You do pay full price for the dining plan (no free days.)