This systematic review investigated the possible effects of exposing infants to formal activities in aquatic environments. A literature search of eight databases was concluded on 12 December 2022. Studies were eligible if they: (i) focused on 0–36 months of age infants, (ii) addressed the exposure of infants to formal aquatic activities, and (iii) compared the ‘same condition of aquatic exposure with the control’ or ‘before and after exposure’. The PRISMA protocol was used. Articles considered for inclusion (n = 18) were clustered in the health, development, and physiological outcome domains. The results show that research is focused on indoor activities, mainly in baby swimming programs and baby aquatic therapy interventions. Swimming and aquatic therapy practices are generally safe for babies’ health, and there are benefits to preterm and newborns exposed to aquatic therapy once the physiological parameters are maintained in normal and safe patterns. A positive effect is also suggested in general gross and fine motor skills, visual motion perception, cognitive flexibility, and response selection accuracy for infants who participated in aquatic programs. Further investigation with high-quality experimental designs is required to establish the effect of exposure of infants to formal aquatic activities (Systematic Review Registration: CRD42021248054).