Civil Engineering Department, Marmara University, 41420 Kadikoy, Istanbul, Turkey E-mail: esin.bozkurt@marmara.edu.tr Manuscript received online 20 October 2020, revised and accepted 31 October 2020 There is an ongoing relationship in terms of fishing, tourism and transportation both socially and economically on the coasts. It is important to investigate the dynamics of the coasts in terms of people who use them as recreation areas and aquatic creatures that use them as living spaces. For this purpose, the water quality was examined by measuring the sea water temperature, pH, dissolved oxygen, salinity, and concentrations of As, Cd, Cu, Pb, Ni, and Zn daily between 5-14 August 2020 in Armutlu, Yalova. The levels of parameters were close to the previous studies. The order of heavy metal concentrations was: As > Pb > Zn > Cu > Ni > Cd. Armutlu coastline should be saved from pollution, destruction, and crass development.