This systematic review and meta-analysis aimed to evaluate the effectiveness of aquatic therapy on pain, sleep quality, psychological symptoms, quality of life, and health status in people diagnosed with fibromyalgia. We searched PubMed, CINAHL, The Cochrane Library, PEDro and Scopus databases. Articles were eligible if they were randomised controlled trials (RCTs) analysing the effects of aquatic therapy in adult people diagnosed with fibromyalgia, and published by October of 2022 in English or Spanish. The Cochrane Risk of Bias tool was employed to conduct the methodological quality assessment of the encompassed studies, and the overall quality of evidence for each comparison was determined using the GRADE approach. Of 375 articles found, 22 met the inclusion criteria. Forest plot analysis of Pittsburgh sleep quality index at short- and mid-term follow-up showed a trend in favour of aquatic therapy, although not statistically significant, with weighted mean difference (WMD) = -1.71 (95% CI: -4.17 to -0.75, p = 0.17). Heterogeneity was substantial (χ2 = 8.74, df = 5 (p < 0.000001; I2 = 95%). Relating the pain outcome by fibromyalgia impact questionnaire (FIQ) short term showed a trend in favour of the aquatic therapy group with WMD = -5.04 (95% CI: - 9.26 to - 0.82, p = = 0.02) with heterogeneity χ2 = 11.07, df = 4 (p = 0.03; I2 = 64%). Great heterogeneity was found between trials in medium term. This systematic review and meta-analysis demonstrated the effectiveness of aquatic therapy as an adjunct treatment to usual care in people suffering from fibromyalgia. Aquatic therapeutic exercise improves the symptomats of sleep quality, pain, and quality of life of adults with fibromyalgia. Further research on long-term outcomes may contribute to the currently available evidence. Aquatic therapy or aquatic exercise refers to the application of aquatic properties to design a therapy program to improve patient functionality. Water is an environment that, due to its properties, provides the opportunity for the patient to undertake global activity and to apply physiotherapy that, outside the water, could not possibly be done [ 5 ]. The four main physical principles of water are buoyancy, resistance, hydrostatic pressure and thermal conduction [ 5 ]. The decrease in pain is attributed to a conjunction of factors, i.e. exercise, warm water and buoyancy that activate mechanoreceptors and thermoreceptors. Immersion in warm water increases blood flow and therefore oxygen in the blood, eliminating catabolites and reducing the level of IL-8 and noradrenaline, responsible for activating nociceptors [ 5 ]. This sensory and motor hyperstimulation blocks nociceptors and reduces the patient’s pain. The physiological effects provided by aquatic therapeutic exercise results from immersion in warm water (26–32 °C) [ 6 , 7 ], which reduces the activity of the sympathetic nervous system and can decrease inflammation and pain perception in subjects with musculoskeletal disorders. Benefits are also obtained through hydrostatic pressure, as compressive stresses on the joints are reduced and allow for functional exercise with gravitational discharge. This property allows for more intense exercise, strength, and range of motion with less cardiovascular stress [ 7 ]. However, one high-quality review incorporating 10 trials on hydrotherapy and spa therapy provided little evidence to suggest superiority over the comparator intervention [ 1 ]. In recent decades, aquatic therapy studies have been conducted suggesting that the physical benefits of water and the effects of exercise are effective in improving the symptoms of The sea group presented a most expressive improvement in BDI score in post-treatment ( F = 2.418, P < 0.0001) Aerobic exercises performed in sea water should be a safe and of low-impact therapeutic option in depression symptoms. BORG perceived exertion scale, VAS, FIQ, SF-36, PSQI, BDI, Muscle pain. Burn by Portuguese caravel Andrade et al. (2019) 23 n = 54 ♀ (30–60 yr) M = 48 ± 8 vs 47± 8 Follow-up at 16 and 32 weeks 16 wk. of intervention - Aquatic exercise ( n = 27): twice a wk 10-min warmup, 30-min aerobic exercise and 5-min cooldown - Control group( n = 27) Variable VAS fatigue [ F (1.27) = 4.68; p = 0.03] was improved. The bias of blinding participants was considered difficult to follow, especially when delivering an aquatic intervention. None of the previous reviews on aquatic therapy has specifically analyzed sleep quality. Nevertheless, the systematic review of Bidonde [ 6 ] recruited a total of 881 patients from 16 studies, where the interventions were nine studies comparing aquatic exercise versus a control group, five studies comparing aquatic exercise versus land exercise and two studies comparing two different aquatic exercise interventions. Between the water exercise and land exercise groups, no significant differences were obtained except for muscle strength, which was in favour of land exercise. This corroborates the results presented in our review, in which aquatic exercise did not provide statistically significant different results when compared to land exercise, indicating that one modality is not superior to the other. For the outcomes in terms of applying aquatic aerobic exercise, it was found that the mechanisms provided by water immersion are directly related to the results. We should also highlight the acute benefits of the temperature of the water can enhance the parasympathetic response and modulate the sympathetic response, which could lead to a reduction in stress-related hormones such as adrenaline, noradrenaline and cortisol and allow the release of serotonin, inducing a momentary improvement in clinical symptoms [ 47 , 48 ]. Furthermore, an extensive study by Becker [ 49 ] on aquatic therapy demonstrated a reduction in pain, improvement in sleep patterns and a positive impact on fibromyalgia and mood-state disorders when compared with land-based exercise programs.