The joy and excitement of going on a Disney vacation with a toddler starts long before you all get to the theme parks. The first moment they find out that they are going to visit Disney World for the first time is just magical. You have the chance to see their faces light up, their eyes sparkle and a huge smile take over their faces. Some kids scream, jump, laugh; others cry and hug you, I even remember the daughter of a friend, who was incredibly skeptical about the news and assumed that her parents were pulling a prank on her until they finally convinced her that it was true and she got incredibly excited.
A great way to tell your children that you are going to Disney, then, is to make it a surprise. Personally, I have always kept it simple: a riddle or a rhyme to let the oldest one know has been the most I have gone to, but I have heard some great ways of giving the news. My sister once made a scavenger hunt with Disney themed clues all around the house. By the end of it, there was a box with what would be their Disney uniforms and some trinkets, and her kid loved it! I have also heard of people who hire a voice actor to call them and invite the kids to Disney World pretending to be a Disney character, which is really fun.