The objective of this study was to evaluate whether early postpartum exercise is associated with changes in pelvic symptom severity, pelvic floor muscle strength, and diastasis recti abdominis (DRA) from 3 to 12months postpartum. In this prospective cohort study, 504 participants with and without pelvic symptoms (pelvic girdle pain, stress urinary incontinence, vaginal heaviness) were followed. At 3, 6, 9, and 12months postpartum, we assessed pelvic symptoms, exercise behavior (by questionnaires), pelvic floor muscle strength (by vaginal palpation), and DRA (by caliper measurement). Based on the 3-months questionnaire, participants were categorized as nonexercisers (n = 105), minimal low-impact exercisers (n = 249), regular low-impact exercisers (n = 117), and high-impact exercisers (n = 32). Between-group differences and within-group changes from 3 to 12months were calculated using Chi-square tests, Kruskal-Wallis tests, and Friedman analysis of variance. At 3months, no differences in symptom prevalence were seen between the groups. Nonexercisers reported higher pelvic girdle pain severity and had weaker pelvic floor muscles. The within-group analysis showed that pelvic girdle pain severity did not change in nonexercisers or high-impact exercisers, but decreased in minimal and regular low-impact exercisers. Stress urinary incontinence increased in nonexercisers from 3 to 12months, while it remained unchanged in regular low-impact and high-impact exercisers, and decreased in minimal low-impact exercisers. Across all groups, vaginal heaviness and DRA decreased, and pelvic floor strength increased from 3 to 12months. The study indicates that early low-impact exercising is associated with reduced pelvic girdle pain severity during the first postpartum year. Minimal low-impact exercisers also showed a slight reduction in stress urinary incontinence. Conversely, nonexercisers reported an increase in stress urinary incontinence between 3 and 12months postpartum. Physical therapists should encourage women to start with low-impact exercise early after pregnancy. This study highlights the positive effects of starting gentle, low-impact exercise early after childbirth to reduce pelvic girdle pain and urinary incontinence.