We visited on a Friday in July and were pleasantly surprised by the crowds inside the park. Ride wait times were totally manageable (though we didn't hit any of the bigger rides), and bathroom lines were almost nonexistent. But it was a completely different story inside the water park, where it was absolutely packed and slightly chaotic.
I preferred the calmer vibes of the park, but the water attractions were a huge hit with the kids. Much like inside the regular park, there was a lot to do that was geared toward younger kids, which meant the adults didn't have to even bring bathing suits to let the kids enjoy the play areas.
They make it easy to go between the park and the water park with changing areas, drying stations, and even a store full of swimwear and towels if you forget your gear. Keep in mind the water park is actually inside Legoland, so you're required to have a ticket to Legoland first, which you can upgrade to include entrance to the water park for an additional $30.
