This randomized, parallel-group clinical trial evaluates the effectiveness of a continuity of care intervention to improve metabolic control in adults with type 2 diabetes mellitus (T2DM) in the Terres de l'Ebre health region. The intervention, led by the Endocrinology Service at Hospital de Tortosa Verge de la Cinta (HTVC), involves structured, multidisciplinary training and feedback provided by endocrinologists and nurse educators to primary care professionals. Training modules combine theoretical and practical content focused on current diabetes management. Primary care centers are randomized to intervention or control arms. Eligible participants are adult patients with an active diagnosis of T2DM for at least 12 months as of January 2025, registered in the eCAP system. All primary care professionals in intervention centers participate in the training. The intervention is conducted over one year (July 2025-July 2026). Outcomes are assessed at baseline, 6, 12, and 24 months. The primary outcome is HbA1c; secondary outcomes include other health indicators, professional knowledge and engagement, and organizational variables. A qualitative component gathers professional input before and after the intervention to inform future implementation. All data are anonymized to ensure confidentiality.