Choroidal thickness (CT) has emerged as a potential biomarker for predicting myopic progression in adolescents. This longitudinal study aimed to evaluate the predictive value of subfoveal choroidal thickness (SFCT) in determining the rate of myopic progression over a two-year period. A cohort of 300 adolescents aged 12 to 16 years was recruited at Al-Ehsan Trust Eye Hospital and categorized into three groups based on baseline refractive status: emmetropic, low myopic, and moderate-to-high myopic. SFCT and axial length (AL) measurements were obtained using spectral-domain optical coherence tomography and partial coherence interferometry, respectively, at baseline, 12 months, and 24 months. The study found a statistically significant inverse correlation between baseline SFCT and AL elongation (r = -0.45, p < 0.001). Participants with thinner baseline SFCT experienced greater myopic progression, with the moderate-to-high myopic group showing the most pronounced changes (mean AL increase: 0.52 ± 0.08 mm; p < 0.001). Multivariate regression analysis confirmed SFCT as an independent predictor of myopic progression after adjusting for age, sex, and baseline refractive error (β = -0.38, p < 0.001). These findings suggest that SFCT measurement can serve as a valuable tool in identifying adolescents at higher risk for rapid myopic progression, thereby facilitating early intervention strategies.