In this study, the deleterious influence of hot deionized water on adhesively bonded joints was reduced with silicon carbide (SiC) nanoparticles and multi-walled carbon nanotubes (MWCNTs). A gravimetric method was used to study the kinetics of water ingress into the neat and nanocomposite epoxy adhesives. Then, joints were manufactured using the same neat and nanocomposite adhesives and aged for different periods according to the results obtained from the bulk sample tests and finite element modeling. The results showed that the reinforcing effect of nanofillers on the strength was about three times higher for the wet epoxy adhesive compared to the dry one. Moreover, it was found out that introducing 4.4 wt% of SiCs or 0.52 wt% of MWCNTs to the adhesive can compensate the degrading influence of aging under near-saturated condition. Furthermore, the scanning electron microscope (SEM) fractography was used to assess the fracture surfaces of the neat and reinforced samples.