Background: Frequent and short-term repeat visits place significant pressure on primary care-centered health systems, particularly in large metropolitan areas. Istanbul, with its high population density and heterogeneous sociodemographic profile, presents a unique context for understanding short-interval healthcare utilization dynamics. Objective: To examine short-term repeat healthcare utilization following an index primary care visit and to explore how district-level population and socioeconomic characteristics shape early post-visit care-seeking dynamics in a large metropolitan setting. Methods: This retrospective cohort study analyzed protocol records from 225 randomly selected FMUs across Istanbul. A total of 11,101 individuals who presented on 7 July 2025 were followed for 21 days, during which 26,743 healthcare contacts (index family medicine unit visits, recurrent FMU visits, and secondary/tertiary care visits) were captured. FMU repeat visits, higher-level utilization, district-level population density, and socioeconomic development level (SEGE-2022) were analyzed using descriptive statistics and district-level comparative analyses. Results: During the 21-day follow-up period, participants generated a total of 26,743 healthcare contacts. Across the full cohort, the median number of recurrent FMU visits was 0 (IQR 0–1), and the median number of secondary/tertiary visits was 0 (IQR 0–1). Among individuals who had repeat contacts, the median number of recurrent FMU visits was 1 (IQR 1–2), and the median number of secondary/tertiary visits was 1 (IQR 1–2). Repeat visits clustered in the first 7 days, whereas higher-level visits increased between days 10–21. Districts with lower SEGE status and high population density (e.g., Esenyurt, Bağcılar, Pendik, Küçükçekmece, Ümraniye) exhibited markedly higher repeat visit intensity. Spatial patterns indicated substantial clustering in western and socioeconomically disadvantaged districts. Multivariable regression analysis showed that visitor patient status was associated with higher secondary/tertiary care utilization (OR = 1.14, 95% CI 1.04–1.24), while higher SEGE scores were modestly associated with increased repeat FMU visits. Conclusions: Short-term repeat visits in Istanbul appear to be influenced not only by clinical needs but also by broader contextual factors such as socioeconomic disadvantage, population density, and health system organization. These findings suggest potential structural pressures within Türkiye’s primary care-centered system and highlight the potential value of district-specific interventions.