Mittivakkat Gletsjer has retreated continuously since the first observations in the early 1930s. It has the longest glaciological surface mass balance (SMB) record of any peripheral glacier in Greenland. In this study, three different approaches to estimate the mass balance of Mittivakkat Gletsjer are compared to provide a multi-methodic assessment of trends in SMB and to extend the SMB record back to 1959. We utilize the glaciological SMB record (1996-2022), calibrate SMB from the Regional Atmospheric Climate Model (RACMO) to account for previous glacier extents (1959-2022), and use digital elevation models derived from aerial and satellite imagery to calculate geodetic mass balance (MB) (1982-2013, 2014-2023). Glaciological SMB measurements and modelled SMB correlate well (r = 0.84, p < 0.01) and are of the same magnitude as the geodetic MB. The SMB results from RACMO suggest that the SMB at Mittivakkat Gletsjer changed after 1992, with mass losses more than tripling from -0.25 ± 0.46 m w.e. / yr in 1959-1992 to -0.91 ± 0.46 m w.e. / yr in 1993-2022. The period 2014-2022, which is assessed by all three methods, had higher mass loss than preceding periods (glaciological SMB: -1.20 ± 0.30 m w.e. / yr, modelled SMB: -0.90 ± 0.46 m w.e. / yr, geodetic MB: -0.96 ± 0.21 m w.e. / yr). The model reconstruction of SMB since 1959 lies within uncertainties of previous mass balance studies at Mittivakkat Gletsjer and correlates with climate indices. Our findings highlight that the peripheral Mittivakkat Gletsjer experienced a change in mass dynamics during the 1990s similar to what has been estimated for other regions across Greenland. Furthermore, we show that calibrating SMB from RACMO allows for assessing mass changes of glaciers on a subregional scale.