Water kefir is a non-dairy fermented beverage produced by the fermentation of sugar-rich solutions by a symbiotic consortium of Lactic Acid Bacteria (LAB), Acetic Acid Bacteria (AAB), and yeasts embedded in a polysaccharide matrix. Unlike milk kefir, water kefir is suitable for individuals with lactose intolerance, milk protein allergies, and those following vegan diets. This mini review critically examines original research articles investigating the health-related properties of water kefir. Experimental evidence from in vitro  assays and in vivo animal models demonstrates that water kefir exhibits antioxidant, anti-inflammatory, antibacterial, detoxifying, antidiabetic, and gut microbiota-modulating activities. Studies have shown protective effects in experimental models of colitis and type 2 diabetes, as well as mycotoxin detoxification and safety in subchronic toxicity assessments. The bioactive properties are attributed to both viable microorganisms and fermentation-derived postbiotics, including organic acids, Exopolysaccharides (EPS), and phenolic compounds. Despite these promising preclinical findings, well-designed human clinical trials remain scarce. This review synthesizes the current evidence, highlights consistencies and limitations across studies, and identifies directions for future research to establish water kefir as a functional beverage for human health.