Pineapple shell, considered a waste in the juice industry, was used as a reinforcement material to produce biodegradable foam trays (FTs) based on cassava starch by a compression molding process. These foams were prepared with different starch/fiber ratios and then were characterized according to their microstructure and physical and mechanical properties. The starch/fiber ratio of 95/5 showed the lowest values of thickness and density (2.58 mm and 367 kg m−3, respectively). There was a good distribution of the pineapple shell fiber throughout the polymeric matrix. All FTs showed a semicrystalline structure and 95/5 ratio showed the highest crystallinity index (CI) value (39%). In addition, this ratio improved the tensile strength of the FTs, obtaining similar values to expanded polystyrene (EPS) samples, used as the reference material. Nevertheless, all FTs reinforced with pineapple shell fiber showed high water absorption capacity (WAC); therefore, future studies should focus on to improve the physicochemical and structural properties of the cassava starch-based foams, considering the promising potential of this novel biodegradable material for dry food packaging, such as a viable alternative to reduce the use of petroleum-based materials such as commercial EPS trays.