Centennial Sportsplex
222 25th Ave N, Nashville, Tennessee
100% positive
Directions: I know that there's one next to the locker rooms in the swimming pool area (pool is right of the main entrance, bathrooms/locker rooms are across from the stands). i'm pretty sure there isn't a unisex one in the main lobby though and I'm not sure about the ice rink.
Comments: The pool opens at 6am but I'm not sure of the closing times, they're subject to change depending on what events the facility is hosting at the time. There is also a fee in the front lobby for the pool though, the fees vary on age. For college students (w/ student I.D.) it's 7.00$ and the same for Seniors 62 and over, ages 5–17, Disabled, and Active Military. It's 8$ for adults ages 18–61.