Plastic trash in Indonesia has reached 64 million tons per year. Consequently, a solution is required to decrease synthetic plastic waste. A film based on nata de coco has been made as an alternative to biodegradable plastic material using materials consisting of nata de coco, chitosan, and 1% acetic acid. The nata de coco based film was made by varying the composition of chitosan. The variations of chitosan used were 0.1 gram, 0.2 gram, 0.3 gram, and 0.4 gram. The biodegradation test used the soil burial test method by immersing the sample in the soil and the mixed microbial batch method using effective microorganisms 4/EM4 with an estimated time of 15 days. The results of the soil burial test method showed a variation of 0.1 experienced a weight loss of 100%. Meanwhile, variations of 0.2, 0.3, and 0.4 experienced a weight loss of 60-75%. Meanwhile, the results of the mixed microbial batch method showed that the nata de coco-based film underwent biodegradation as indicated by the tearing of the surface of the nata de coco-based film. From these results, nata de coco-based films can be said to be biodegradable plastics.