
Eynal Aqua Park is a unique thermal aqua park operating within the Eynal Kaplıcaları thermal springs complex in Simav, Kütahya Province, Turkey, situated at an altitude of 800 metres amid the natural beauty of the surrounding landscape. The facility is recognised as Turkey's largest open-air aqua park fed entirely by natural thermal water, with spring temperatures exceeding 160°C before being cooled to comfortable bathing temperatures of 38–42°C. The mineral-rich water is abundant in sodium, calcium, bicarbonate, and meta-silicic acid, prized for its therapeutic qualities and celebrated by travellers as far back as the 17th-century Ottoman explorer Evliya Çelebi. The park features a large pool with five water slides alongside bath facilities, restaurants, cafeterias, and tennis courts. Operating hours are 10 AM to 6 PM, with separate access days allocated for women and men throughout the week.