This study systematically reviews the current state of aquatic treatment of neck pain and assesses the scientific evidence of its benefits. The databases PubMed, Scopus, Web of Science and PEDro were searched for relevant reports published from January 1, 2008, to November 7, 2017, using the keywords "neck pain" in addition to "balneotherapy", "spa treatment", "spa", "thalassotherapy", "hydrotherapy", "aquatic therapy" or "aquatic". Inclusion criteria were full-text articles published in journals included in Journal Citation Reports in English and Spanish describing human studies. Case studies, letters to the editor and meeting presentations or other contributions were excluded. Of 367 articles identified, only 13 fulfilled the inclusion criteria: 5 randomized trials, 1 single blind controlled study, 2 pilot studies, 2 observational retrospective studies, 1 prospective study, 1 clinical study and 1 not specified. Participants were 658 subjects with chronic neck pain. Main symptoms and signs treated were neck pain, disability, cervical disc herniation and compromised quality of life. Evidence that aquatic treatment improves quality of life in affected individuals was good in four studies, fair in eight and weak in one. Treatment of neck pain using different waters and techniques reduced pain and disability, and improved functional capacity, quality of life, joint mobility, balance, relaxation and mood.