This dataset contains the estimated source parameters using both Spectral Fitting (SF) method and Generalized Inversion Technique (GIT) for 1,577 earthquakes with magnitude ML1.0-5.7 during the time span 2006-2020 in the Sea of Marmara region. The study area surrounds the Sea of Marmara, close to the megacity Istanbul, with longitudes ranging from 27.3° to 29.35° and latitudes ranging from 40.5° to 40.9°. Source parameters including seismic moment (M_0^SF), corner frequency (f_c^SF), quality factor (Q^SF), and Brune stress drop (∆σ^SF), are estimated and calculated using SF approach (Kwiatek et al., 2011, 2014, 2015) with the Simplex method applied in the optimization process (Nelder & Mead, 1965); source parameters from GIT approach including seismic moment (M_0^GIT), corner frequency (f_c^GIT), and Brune stress drop (∆σ^GIT) are also calculated for the same events. The event information, i.e., event date, original time, event longitude, latitude, depth, local magnitude, is obtained from the seismicity catalog of Becker et al. (2023).