We went to Animal Kingdom and Blizzard Beach on the same day. However, we had been to Animal Kingdom before so skipped some things. If it is your first time and you want to do everything, I would say no. Otherwise, be there before opening time to get in early, see the highlights at Animal Kingdom, go back to the hotel to eat and change, and then proceed to the water park. Keep in mind all the parks are more crowded with longer lines in the afternoon. We did get to go on plenty of slides, tubes etc. even though we did not get there until about 2. That was more than enough for us, since the water parks wear us out faster than any other park (climbing all those steps to the top of each ride).