The use of renewable feedstocks in foam technology is a worldwide demand towards more sustainable materials. Castor oil is a vegetable oil, composed mainly by triricinoglycerol, a natural polyol, suitable for polyurethane foams production. In this study castor oil and a variable amount of microcrystalline cellulose fibers were used in a straightforward one-pot synthesis approach for the preparation of novel biofoams. The ensuing biofoams were characterized by several techniques, including ATR FTIR, SEM, TGA, and their mechanical performance was evaluated by compression mechanical testing and by DMTA. They were (semi-) flexible, with a cell-like morphology, and with reinforced toughness due to the use of microcrystalline cellulose. They had a Young’s modulus varying between 0.188 and 1.06 MPa depending on the amount of microcrystalline cellulose used, and were thermally stable up to 267 oC. The properties of these novel biofoams enable them to be strong candidates to be used as tough, energy absorbing foams, advantageously prepared using renewable-based resources.