The Sultaniye Thermal Springs on the southwestern shore of Lake Köyceğiz are reached by a pleasant boat trip across the lake from Dalyan, typically taking about an hour. The springs feed both open-air pools and hot mud baths at around 40°C, rich in minerals including chloride, bromide, and hydrogen sulphide. The experience — coating yourself in mineral mud, letting it dry, then washing off in the warm pool — is as enjoyable as it sounds.
The setting is lovely: the springs are at the lake's edge surrounded by trees, with views across the water to the hills beyond. The boat trip there passes through the Dalyan Delta's reed beds and is an attraction in itself. Most operators combine Sultaniye with a stop at the Kaunos tombs and Iztuzu Beach in a day-long circuit.