Hello, Andrea,
Both
Disney's Blizzard Beach Water Park and
Disney's Typhoon Lagoon Water Park have large dressing rooms with changing areas, showers, and restrooms. You can also rent lockers (small or large) for a small fee as well as towels. The dressing rooms and locker rentals are located near the front of both parks; just follow the signs when you arrive or ask a cast member to point you in the right direction.
Last year was our first year visiting the water parks with our
MagicBands, and I loved the freedom they provided. No wallet, park tickets, room key, or money! Aside from sunscreen and sunglasses, we only need our MagicBands. It was great traveling so light! However, if you plan on using a free life jacket, you are required to leave a form of identification.
Have a magical trip and enjoy the water parks. Please let us know if we can answer any further question.
-Kara