A new process for the preparation of non-isocyanate polyurethane (NIPU) flexible foams has been implemented. Biobased amino-telechelic NIPU oligomers were prepared by an organo-catalyzed transurethane polycondensation reaction of fatty biscarbamates with fatty diols and diamines. The obtained oligomers were reacted with a biobased multi-epoxide molecule as crosslinking agent, in the presence of a poly(hydromethylsiloxane) or its copolymer as foaming agent and surfactant. The crosslinking and foaming reactions were monitored by rheometric, volumetric and FTIR studies. The foams can be obtained in <30 min at 100 °C or in 14.5 h at room temperature. The prepared foams displayed cell diameters in the range of 210 to 430 μm associated with densities in the range of 130 to 400 kg/m3. They also exhibited thermal stabilities above 300 °C, as well as a soft character attested by negative Tg values ranging from −10 to −28 °C, and low values of the Young modulus varying from 1.0 × 104 Pa to 6.3 × 104 Pa. The recovery time, hysteresis loss and the firmness of these foams were found to be dependent on their chemical structures.