Echosounders are used to monitor suspended sediment concentrations (SSC) in coastal management studies and to monitor dredge plumes. Due to the dependency on sediment properties like particle size, shape and density, performance of single frequency measurements is limited when sediment properties are changing. Using multi-frequency measurements, mean particle sizes can be derived and used to (partly) adapt to these variations. Based on field measurements in the coastal waters around Texel, performance of the single and multi-frequency methods was assessed under steady and varying measurement conditions. While similarly high performance was obtained under steady conditions, the multi-frequency method outperformed the single frequency method significantly when measurements were taken over multiple tidal stages. Also, SSC estimations became less sensitive to selection of frequency. If further developed, the potential of SSC quantification using echosounders is significantly increased.