Aim To explore the effects of a dementia‐specific, aquatic exercise intervention on behavioural and psychological symptoms in people with dementia (BPSD). Method Residents from two aged care facilities in Queensland, Australia, received a 12‐week intervention consisting of aquatic exercises for strength, agility, flexibility, balance and relaxation. The Psychological Well‐Being in Cognitively Impaired Persons Scale (PW‐BCIP) and the Revised Memory and Behaviour Problems Checklist (RMBPC) were completed by registered nurses at baseline, week 6, week 9 and post intervention. Results Ten women and one man (median age = 88.4 years, interquartile range = 12.3) participated. Statistically significant declines in the RMBPC and PW‐BCIP were observed over the study period. Conclusion Preliminary evidence suggests that a dementia‐specific, aquatic exercise intervention reduces BPSD and improves psychological well‐being in people with moderate to severe dementia. With further testing, this innovative intervention may prove effective in addressing some of the most challenging aspects of dementia care.