Background <p>To evaluate color stability, surface roughness, and microhardness of flowable nanohybrid resin composites following immersion in different media.</p> Methods <p>Polofil NHT Flow (VOCO GmbH), G-aenial Universal Injectable (GC DENTAL PRODUCTS CORP), and Tetric N-Ceram (Ivoclar Vivadent) were used. From each tested resin composite, 50 disc-shaped specimens (10-mm diameter × 2-mm thickness) were performed. Each group was categorized into five subgroups according to immersion media (<i>n</i> = 10): (1) control (without immersion), (2) artificial saliva, (3) coffee, (4) cola, and (5) energy drink. Color stability, surface roughness, and microhardness were evaluated. Data were analyzed through two-way ANOVA, Tukey’s post-hoc, and Pearson correlation coefficient tests (<i>p</i> &lt; 0.05).</p> Results <p>For color change, no statistically significant differences were observed among the resin composites regarding artificial saliva (<i>p</i> = 0.78), coffee (<i>p</i> = 0.93), and cola (<i>p</i> = 0.09), while there was a significant difference between them regarding energy drink (<i>p</i> &lt; 0.05). The highest surface roughness mean value was recorded with Polofil NHT Flow, which showed an increase in surface roughness after immersion in energy drink (0.32 ± 0.06&#xa0;μm) compared to the control subgroup (0.22 ± 0.08&#xa0;μm). For all resin composites, there were significant reductions in microhardness with all immersion media in comparison to the control subgroups (<i>p</i> &lt; 0.05).</p> Conclusions <p>For color stability, energy drink and coffee had the most negative effect on all tested resin composites. Energy drink caused the highest discoloration with G-aenial Universal Injectable and the highest roughness with Polofil NHT Flow. All tested resin composites showed a decrease in surface microhardness following immersion in all tested immersion media.</p>