Background: This study aims to describe a prospective clinical cohort of patients with silicone breast implants and suspected Breast Implant Illness (BII). Methods: Women were included in a specialized silicone outpatient clinic at Amsterdam UMC, the Netherlands. Baseline characteristics were collected including medical history, implant details, and symptoms. Experienced physicians categorized BII suspicion as high, moderate, or low, based on symptoms and after exclusion of other probable causes. Additionally, participants completed questionnaires assessing symptoms and daily life impact at baseline, 6 months, 1, 2, and 5 years. For this initial analysis, the results from the first three years of inclusions were collected. Results: Data from 353 women were collected from December 2020–December 2023. At baseline, the most reported symptoms were fatigue, arthralgia, myalgia, and morning stiffness, accompanied by local symptoms in 83.3% of patients. At the clinic, 112 women were categorized as having high suspicion of BII, 147 women as moderate, and 94 women as low. At follow-up, 182 women (51.6%) opted for explantation. Following explantation, women with a high or moderate suspicion of BII experienced more significant symptom improvement, accompanied by a decrease in anxiety and a greater sense of control over their illness, compared to women with a low suspicion of BII. Conclusions: Our study highlights a distinct interplay of systemic and local symptoms among women with suspicion of BII. Women with a high or moderate BII suspicion benefit significantly more from explantation than women with low suspicion. Experienced physicians are pivotal in effectively assessing and guiding this patient group, highlighting the need for tailored clinical approaches.