When disseminated in early childhood education, the One Health concept, which involves human, animal, and environmental health, can provide a consistent, long-term effect on sustainability. Students from the Graduate Program in Environmental and Experimental Pathology at Universidade Paulista thus proposed activities for fifth-year grade students (i.e., “the children”) at Escola Estadual Professor Pedro Voss to discuss the impact of overpopulation on One Health’s balance of sustainability. The students planned the educational activities to be developed in three meetings with the children, who were divided into two groups, each with approximately 30 individuals. In the first two meetings, the activities focused on introducing concepts related to overpopulation, One Health, animal health, ecosystem health, and human health. Board games, word searches, yes-and-no trivia, and puzzles were developed according to the targeted themes and used as tools to introduce their concepts. Each group was exposed to the games for 15 min, in a rotation-per-station system. In the third meeting, all activities were repeated; both groups worked together to reinforce the previously explored concepts. The graduate students verified the efficacy of using games with children as tools for acquiring complex concepts. The learning process success was observed in creating a collaborative artistic panel board decorated with thematic sticker figures freely constructed by the children. The proposed methodology allowed the students to transmit the concepts involved in One Health by using ludic activities to the children, contributing to achieving goals that stretch beyond the university walls.