This study is a protocol for a convergent mixed methods study of frailty and lived experiences in older adults with osteoporosis. In older adults, it causes an age-related decline in bone mineral density that further exacerbates frailty—the geriatric syndrome—and increases the risk of functional decline with psychosocial consequences. The quantitative phase includes a cross-sectional survey measuring demographic data, Edmonton Frail score, activities of daily living, nutritional risk, anxiety and depression, handgrip strength and laboratory parameters, analyzed descriptively, univariate and multivariate binary logistic regression to identify frailty factors. The qualitative phase consists of semi-structured interviews with frail participants to explore their subjective experiences in the context of osteoporosis. In the integration phase, findings from both phases are synthesized for a comprehensive understanding of the phenomenon. The study examines the prevalence and clinical characteristics of frailty, risk factors and subjective experiences of patients. It is registered in the China Clinical Trials Registry under the number ChiCTR2500097059.