Context/ Introduction: Biodegradable plastics manufacture is needed to replace conventional plastics. Aims: Potato starch and its alternative sources such as sweet potato and tapioca have been studied for their potential use in making bioplastics. Methods and Material: Starch was extracted and characterized by microscopic, physicochemical, and spectroscopic methods. Starch, along with other ingredients, was used to prepare bioplastics which were assessed for mechanical properties also biodegradability in soil and water. Statistical analysis used: One Way ANOVA test was used. Results: Tapioca and sweet potato starch had smaller granule size than potato starch. Sweet potato starch showed highest blue value indicating higher amylose content, followed by potato. Higher amylose content and smaller granule size are desirable in preparation of bioplastics. Sweet potato and potato starch, which were completely soluble in water within 2 hours and 91% to 96% biodegraded in soil within one month, were used to prepare bioplastics. Bioplastic with higher carboxymethyl cellulose content had the highest tensile strength of 8.38 MPa and maximum peak load of 2.4 kg. These bioplastics had 210 microns thickness. Conclusions: Sweet potato starch had good yield, smaller granule size and high amylose content. Addition of carboxymethyl cellulose in preparation of bioplastic improved its tensile strength and maximum peak load. These bioplastics can be replaced by the current plastic bags as they were completely biodegradable in soil and water. They can be safely used as bin bags or carry bags wherein they can carry load up to 2.4 kg.