Background Epidermolysis bullosa simplex (EBS) is the most common type of EB, a group of rare genodermatoses. Affected individuals suffer from skin blistering and report a high disease burden. In some EBS subtypes, plantar keratoderma (PK) has been described. Objectives This study investigated the presence and correlation of PK with body mass index, pain and mobility in EBS. Methods Individuals (n = 157) with genetically characterized EBS were included in this retrospective cohort study, and clinical data were collected over 16 years (referral patients to the largest German EB centre). Descriptive statistics and mixed linear models were used to assess correlations. Results PK was found in 75.8% of patients beginning at a mean age of 4.3 years. Both focal and diffuse PK were observed, and 60% of adults with localized and severe EBS were preobese or obese, with ˜30% of patients reporting severely reduced mobility. The presence of PK, especially diffuse PK, correlated significantly with local infections, obesity, pain and requirement of a wheelchair. Conclusion Along with treating skin fragility and blistering, PK should be considered a potential marker of increased morbidity and may represent a target of EBS therapy development.