To investigate the safety, feasibility and potential efficacy of balance training in adults with cerebral palsy.Phase 2, assessor-blinded randomized controlled trial.Outpatient rehabilitation facility.A total of 17 ambulatory adults with cerebral palsy.Participants were randomly allocated to an eight-week, once-weekly, small group programme of balance training, or seated attention control activity. Balance training was individually tailored using the Balance Evaluation Systems test.Primary focus was feasibility, addressed by recruitment, retention, adherence, and safety. Efficacy was primarily evaluated with the Ambulatory Self-Confidence Questionnaire and the Balance Evaluation Systems test, at intervention conclusion and Week 24. Secondary outcomes included gait speed, walking distance, falls efficacy, fatigue, quality of life, and global impression of change.Interventions were safe and feasible with no major adverse events. Adherence was high. At eight and 24 weeks, there were negligible between-group differences in Balance Evaluation systems test total. At 24 weeks, there was a small, non-significant between-group difference in favour of the balance group with effect sizes of 0.14 for ambulatory self-confidence, 0.10 for falls efficacy, and 0.12 for fatigue. There were significant between-group differences for self-reported walking confidence and balance change, in favour of the balance group at Weeks 8 and 24 (p < 0.05).A customised balance programme is feasible and safe for ambulant adults with cerebral palsy. Small effects from balance training in selected outcomes occurred. Study replication with at least 38 participants per group to confirm efficacy is warranted.