The natural springs here are home to wild trout and eels, which you can peer at through an underwater viewer, and plenty of animals, including tuatara (a native reptile) and native birds. The star feature is the National Kiwi Hatchery (tour only $24, with park admission $10), which hatches around 120 chicks a year. Excellent 30-minute tours, departing on the hour, take you backstage to view the incubator and hatchery areas and three adult kiwi.
The centre also has interpretive walkways and a 'Big Splash' water ride.
Rainbow Springs is right beside Skyline Rotorua.
