Active surveillance (AS) has emerged as a key strategy for managing low-risk prostate cancer (PCa), offering an alternative to immediate treatment. Initially, AS relied on prostate specific antigen (PSA) testing, digital rectal examinations (DRE), and systematic biopsies. Early studies using these methods demonstrated favourable long-term outcomes. However, the integration of MRI into diagnostic protocols has transformed AS, improving tumour detection, reducing unnecessary biopsies, and enabling targeted sampling of suspicious areas. Despite these advancements, MRI has also led to a grade shift, with some men initially diagnosed with grade group (GG) one disease being reclassified to higher grades, raising concerns about overtreatment, as GG two has historically been considered clinically significant. The DETECTIVE study found that men eligible for AS after combined systematic and MRI-targeted biopsies do not need confirmatory biopsies. Improved alignment in Gleason Grade (GG) between targeted biopsies and prostatectomy specimens reduces the need for standard confirmatory biopsies, especially compared to diagnoses based solely on systematic biopsies. However, repeat biopsies every two to three years remain crucial for detecting disease progression or addressing prior under sampling. While histopathology is the gold standard, repeat biopsies are often underutilised in practice, potentially compromising accurate monitoring. The timing and frequency of repeat biopsies, along with expanding AS eligibility criteria, are evolving in response to the grade shift observed with MRI-targeted biopsies. MRI has become indispensable in AS for detecting clinically significant PCa. Although the European Association of Urology (EAU) guidelines do not yet recommend serial MRIs, their use in follow-up could enable early detection of aggressive cancers. MRI frequency should align with repeat biopsy schedules, typically every two to three years, with more frequent scans for high-risk patients. The high negative predictive value (NPV) of MRI can help rule out progression in low-risk patients, but MRI findings alone should not dictate treatment decisions. Instead, MRI changes should prompt confirmatory biopsies to verify progression before considering active treatment. Risk stratification for repeat biopsies relies on predictors such as PSA density, MRI findings, and previous biopsy results. Men with stable, low-risk disease – indicated by low PSA density and stable MRI findings – may avoid standard repeat biopsies. The EAU guidelines now suggest serial MRI in some cases to identify low-risk patients, reducing the burden of unnecessary biopsies while focusing on those at higher risk. The integration of MRI into AS introduces challenges, including ensuring high-quality imaging and addressing the capacity for frequent follow-up scans. The definition of clinically significant PCa and the criteria for discontinuing AS remain debated, particularly considering the grade shift caused by MRI-targeted biopsies. Advances like dynamic surveillance could enhance prediction accuracy, but their integration into routine practice is still evolving. Additionally, the adoption of transperineal biopsies, which reduce infection risks, may influence biopsy strategies during AS. In conclusion, AS remains a vital approach for managing low-risk prostate cancer. By incorporating MRI and other modern diagnostic tools, AS aims to minimise overtreatment while optimising patient outcomes. Regular MRI, combined with factors like PSA density, can guide decisions on repeat biopsies, enabling tailored AS strategies for individual patients. However, challenges such as standardising imaging quality, defining clinically significant disease, and integrating new technologies must be addressed to refine AS further.