Submicrometer-sized α-SiC powder was mixed in an aqueous solution at pH 5.0 with the following Al₂O₃ (1-2 vol% against SiC)-Y₂O₃ (0.94-1.6 vol%) sintering additives: sample A-Al₂O₃ powder plus Y₂O₃ powder, sample B-Al₂O₃ powder plus Y₂O₃ powder and polyacrylic acid dispersant, sample C-Al₂O₃ powder plus Y³⁺ ion adsorbed and sample D-Y³⁺ ion adsorbed. The prepared suspensions were consolidated by filtration through a gypsum mold. Green compacts were densified to a 96.2-99.3% relative density at 1800-1950°C under a pressure of 39 MPa for 2 h in an Ar or reduced atmosphere. The sinterability of SiC became higher in the following order: sample D<sample C<sample A≈sample B. The sinterability of samples A and B was comparable to that of SiC hot-pressed with Al₂O₃. Dense SiC with Y₂O₃ or Al₂O₃ plus Y₂O₃ showed the following excellent mechanical properties: average four-point flexural strengths of 565-719 MPa, fracture toughness of 5.0-6.2 MPa•m^1/2, Weibull modulus of 5.4-11.4 and Vickers hardness of 19-22 GPa. Suppression of grain growth in SiC enhanced the mechanical properties.