Background: Complex regional pain syndrome type I (CRPS-I) is a condition characterised by pain, swelling, loss of function, trophic skin changes and vasomotor dysfunction. Biophysical stimulation with a specific combination of pulsed electromagnetic field (PEMF) parameters exerts an anti-inflammatory effect, supporting the rehabilitation process. Materials and methods: We recruited 32 patients with CRPS-I of the foot or ankle, previously treated with an initial course of IV neridronate. Participants were randomised to one of two groups: a treatment programme combining PEMF (1.5 mT, 75 Hz; I-One ® therapy, IGEA) for 4 h a day for 60 days and exercises for 30 min a day for 6 weeks (I-One ® therapy group), or treatment with exercise only (control group). Patients were clinically assessed at 3, 6 and 12 months with: Visual Analogue Score (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score, allodynia, hyperalgesia, pain during passive range of motion (ROM), oedema, Roles and Maudsley scores and non-steroidal anti-inflammatory drug (NSAID) intake. Results: In both groups, VAS was significantly reduced and AOFAS improved significantly compared with baseline at all follow-up points. The I-One ® therapy group saw statistically significant improvements compared with the control group at all follow-up points, not only in terms of VAS and AOFAS scores, but also in the resolution of allodynia, hyperalgesia and pain during passive ROM. At 3 months, the I-One ® therapy group also showed a significantly lower intake of NSAIDs. The I-One ® therapy group showed better patient satisfaction outcomes, with significantly lower Roles and Maudsley scores compared with the control group at 6 and 12 months. Conclusions: I-One ® therapy in association with a rehabilitation program may offer additional benefits in terms of pain reduction, functional recovery, oedema, allodynia and hyperalgesia resolution and NSAIDs use in CRPS-I of the foot and ankle. Trial registration: registered on the ClinicalTrials.gov platform (NCT05922618) on 6 August 2023. Level of evidence: Level II, therapeutic study.