Recycled natural fibers and biopolymers with sustainable, eco-friendly, and biodegradable properties are receiving increased attention. The moisture absorption and swelling of natural fiber composites adversely influence their mechanical properties and applications. In this research, bio-based epoxy polymers that are reinforced with recycled woven jute fabrics were subjected to water immersion tests in order to study the effect of water absorption on their mechanical and geometrical properties. For comparison, petroleum-based epoxy polymers that are reinforced with new woven jute fabrics were also subjected to the same tests. The effect of fiber percentage on water absorption, thickness swelling, and volume swelling was measured as a function of immersion time. It was observed that water absorption and swelling behavior were higher in bio-based epoxy than in petroleum-based epoxy composites. The stress decreased and the strain increased after water immersion in both composites. However, the rates of change in stress and strain were much more significant for composites made with bioepoxy.