Diabetes mellitus (DM) is a complex metabolic disorder associated with a heightened risk of cardiovascular events, largely driven by a hypercoagulable and hypofibrinolytic state. The pathophysiological interplay between chronic hyperglycemia, oxidative stress, insulin resistance, and systemic inflammation fosters profound alterations in the coagulation cascade, endothelial function, and platelet activity. This narrative review synthesizes evidence from studies published between 2008 and 2026, focusing on coagulation and platelet-related biomarkers selected based on their biological relevance to thrombosis, endothelial dysfunction, and inflammation, as well as the availability of clinical and interventional data across different forms of DM. Although there are numerous biomarkers involved in the pathogenesis of various forms of diabetes, this narrative review critically examines key coagulation biomarkers—including D-dimer, fibrinogen, prothrombin, tissue thromboplastin or tissue factor, P-selectin, soluble urokinase plasminogen activator receptor, thrombomodulin, plasminogen activator inhibitor-1, von Willebrand factor, and β-thromboglobulin—across distinct diabetes subtypes, including type 1, type 2, gestational, and secondary forms linked to endocrinopathies and pancreatic diseases. The literature reveals substantial subtype-specific heterogeneity in hemostatic alterations. For instance, Type 1 DM is characterized by early endothelial dysfunction and platelet activation, while Type 2 DM presents with elevated coagulation factors, impaired fibrinolysis, and a proinflammatory milieu. Gestational DM exhibits pregnancy-specific changes in coagulation, yet distinguishing them from obesity-related effects remains challenging. Secondary diabetes forms, such as those associated with Cushing’s syndrome or pancreatitis, further underscore the diversity in thrombotic risk profiles. Among the coagulation and platelet activation biomarkers reviewed, fibrinogen, P-selectin, and plasminogen activator inhibitor-1 demonstrate the most consistent associations with glycemic control, vascular dysfunction, and therapeutic modulation, particularly in type 2 diabetes, suggesting greater potential for clinical translation. In contrast, evidence for markers such as D-dimer, tissue factor or tissue thromboplastin, and soluble urokinase plasminogen activator receptor remains heterogeneous and insufficient for routine clinical application. By synthesizing mechanistic insights and clinical data, this review highlights the urgent need for subtype-tailored coagulation assessment in diabetes management. A better understanding of the dynamic alterations in coagulation pathways may facilitate earlier detection of vascular complications and inform personalized antithrombotic strategies.