This paper presents phase-equilibrium pressure-temperature data for the clathrate hydrates formed in six three-component systems each consisting of a hydrate-forming gas, a water-soluble freezing-point depression material, and water. These systems are difluoromethane + propan-2-ol + water, difluoromethane + 2-methyl-2-propanol + water, difluoromethane + 2-propanone + water, krypton + propan-2-ol + water, krypton + 2-methyl-2-propanol + water, and krypton + 2-propanone + water. The temperature range over which the phase-equilibrium measurements were performed using each system extended to (268.65 to 266.75) K on the lower side and (284.05 to 293.35) K on the higher side. The phase-equilibrium temperatures in the three difluoromethane-containing systems were found to be lower than that in the binary difluoromethane + water system at the same system pressure above 0.2 MPa at which the equilibrium temperature in the binary system is nearly 275 K. On the contrary, the phase-equilibrium temperatures in the three krypton-containing systems were found to be substantially higher than that in the binary krypton + water system throughout the measurement range for each system.