Uchan-su (Ukrainian: Учан-Су, Russian: Уча́н-Су Crimean Tatar: Uçan Suv), is a waterfall on the the river Uchan-su on the southern slopes of the Crimean Mountains. The name translates from the Crimean Tatar language for 'swift water' .
Uchan-su is a popular tourist attraction and is the highest waterfall in Ukraine. Located 7 km from the city of Yalta halfway to Ai-Petri Mountain. The waterfall is 98 meters high at an altitude of 390 meters and is most powerful during the spring when it fed by snow melt in the mountains.