Background and aims. To assess the color, translucency and masking properties of novel flowable giomers. Methods. Three flowable giomers were used for the fabrication of 1-mm thick samples (n=126) in three consistencies (Beautifil flow Plus X F00; Beautifil flow F02; Beautifil flow Plus X F03, Shofu Dental Corporation, Japan) and two shades (A2 and A3). The relative spectral reflectance was recorded over white, black, C3, and a tested-sample colored background. Lightness (L*), and color coordinates a* and b*, Relative Translucency parameter (RTP00) and masking capacity of C3 background were calculated; differences in color and translucency were compared with thresholds for perceptibility and acceptability (PT and AT). Statistical analyses used significance tests for paired samples. Results. All tested materials displayed increased values of L*: for A2 F00=86.16(±0.86), F02=86.39(±0.63), F03=86.40(±0.63); for A3: F00=84.24(±0.58), F02=83.34(±0.3), F03=84.19(±0.4), as well as of RTP: for A2 F00=30.34(±0.88), F02=31.37(±0.94), F03=31.11(±1.15), for A3 F00=29.64(±1.64), F02=30.79(±1.02), F03=30.1(±1.26). For A2 samples, the masking capacity was significantly different for all materials, whilst for A3 there were differences only between F00-F03 and F02-F03. Conclusions. The tested flowable giomers proved high lightness and translucency. The color differences between the materials with the same designation were below the perceptibility threshold in most cases. In addition, the differences in relative translucency parameters ranged between the perceptibility and acceptability thresholds. All tested flowable giomers had an unacceptable masking capacity for a C3 background.