Abstract Background In North Karelia Finland, a team-based service model was implemented in some municipalities’ primary healthcare (PHC) centers during 2020. In this team-model, a healthcare customer contacts a nurse who initiates the service process immediately. Nurses can also consult or direct customers to other healthcare professionals and arrange physical appointments if needed. The aims of the model are improved customer and personnel experience and satisfaction, and improved quality and effectiveness of care. We assess the effect of this team-model on treatment levels, measurement activity, and health care usage among patients with type 2 diabetes (T2D). Methods Patients with T2D were identified using the ICD-10 code E11 from the regional electronic health records. The data include all patients diagnosed by 2016 who were alive and residing in North Karelia in 2023 (N = 6312). Diabetes-related contacts with nurses or doctors in outpatient PHC and specialized healthcare (SHC) were considered, along with measurement activity and levels of glycated hemoglobin (HbA1c) and low-density lipoproteins (LDL) between the years 2017 and 2022. Annual differences between areas were analyzed using logistic and linear mixed models. Results In 2017, patients’ mean age was 66 and age range 20-93. The proportion of men was 55% and 45% resided in team-model areas in 2023. The team-model increased T2D-related outpatient PHC remote contact with nurses for a couple of years. But eventually they decreased to a lower level than before. Additionally, the team-model reduced the number of other contacts. An increased difference between areas in measurement activity on HbA1c and LDL levels was also observed. But the difference between areas in proportion of those who achieved treatment targets stayed unchanged. Conclusions In the long-term, the team-model reduced the number of T2D-related contacts and increased the measurement activity of HbA1c and LDL, but it had no effect on treatment levels. Key messages • Team-based service models might potentially reduce service use in the long term. • More research and evidence are needed on the effectiveness and cost-effectiveness of team-based service models.