To respond to continuous and unforeseen organizational changes in STEM teamwork, team members must have soft skills that are transversal, balanced and sustainable over time. The objective of this study was to determine the change and stability of group cohesion, evaluated using a sociometric method, and the perceived adaptation of skills to promote teamwork, evaluated using a psychometric scale with appropriate validity and reliability, over the medium term (2018-2023) to support future psychosocial interventions for the development of teams. The main results show a) a substantial change in group cohesion and a significant change in the election status of the leader, b) stability of the group’s contribution to autonomy in decision-making and a significant improvement in communication for the understanding of goals, c) high satisfaction with the management and handling of interpersonal conflicts and d) a significant change in group identification. A strength of the group was the continued absence of attitudes of nepotism and careerism. The dynamics of the STEM group in the medium term (6 years) consisted of maintaining a stable level of group cohesion and skills adaptation to teamwork, mainly identification, communication oriented to improve the understanding of goals and the management of interpersonal conflicts. This study shows that a priority for developing stable and efficient teams is to improve group cohesion and the skills of cooperation, coordination and integrity among members.Keywords: Team work, STEM group, Soft skills, Group cohesion, Team adaptation, Cross-sectional repeated study.