Objective To examine prospectively self-reported flare characteristics and their longitudinal association with disease activity and patient-reported outcomes (PRO) in patients with rheumatoid arthritis (RA). Methods Consecutive RA patients with 28-joint count Disease Activity Score based on C-reactive protein (DAS28-CRP) < 3.2 and no swollen joints were examined at baseline, Month 6, and Month 12. Assessments included joint counts, DAS28-CRP, visual analog scale–evaluator’s global assessment (EGA), and PRO. Every third month, patients completed the Flare Assessment in Rheumatoid Arthritis and RA Flare Questionnaire, and disclosed self-management strategies. Flaring and non-flaring patients were compared and longitudinal associations between self-reported flare status (yes/no) and disease activity, PRO, and treatment escalation were explored. Results Among 80 patients with RA [74% females, mean (SD) age 63 (10) yrs, disease duration 11 (7) yrs, and baseline DAS28-CRP 1.9 (0.6)], 64 (80%) reported flare at least once during 12 months. Fifty‑five percent of flares lasted less than 1 week. Common self-management strategies were analgesics (50%) and restricted activities (38%). Patients who reported being in flare had consistently higher disease activity measures and PRO compared to patients without flare. In a partly adjusted model, all flare domains, patient-reported swollen and tender joint counts and disease activity measures were associated with flares. In fully adjusted analyses, present flare was independently associated with pain (OR 1.85, 95% CI 1.34–2.60), patient-reported swollen joints (OR 1.18, 95% CI 1.03–1.36), and higher EGA (OR 1.15, 95% CI 1.04–1.28). Treatment escalation was associated with present flare (p ≤ 0.001). Conclusion In RA, self-reported flares were frequent, mainly managed by analgesics, substantiated by higher disease activity measures, independently associated with pain and patient-reported swollen joints, and related to treatment escalation.