The objectives of this work were to develop biodegradable trays from cassava bagasse and polyvinyl alcohol (PVA) incorporated with clove (CEO) or oregano (OEO) essential oils, to study their antimicrobial activity and to investigate the effects of incorporating these essential oils on the mechanical properties, water absorption capacity (WAC) and sorption isotherms of the tray with the best antimicrobial activity. The trays were produced by baking 97.5% (w/w) cassava bagasse with 2.5% (w/w) PVA. CEO or OEO was added to the trays using two methods: direct incorporation (6.5 to 10.0%) and surface coating (2.5 to 7.5%). Trays with OEO prepared by surface coating showed the highest antimicrobial activity, as they were effective against molds, yeasts, and Gram-positive and Gram-negative bacteria. The addition of OEO to the cassava bagasse-PVA matrix resulted in less resistant and more flexible trays, with a decrease in the water absorption and adsorption capacities.