Low-salinity waterflooding (LSW) and smart water injection have emerged as leading techniques in Enhanced Oil Recovery (EOR), with significant potential to optimize oil production from sandstone and carbonate reservoirs. Over the past decade, advancements in the understanding of ion exchange, wettability modification, multi-ion interactions, and hybridization with chemical EOR methods have shifted LSW from a laboratory observation to a field-validated recovery strategy. This review integrates current progress in low-salinity, smart water, and hybrid LSW-chemical methods, highlighting breakthrough findings on nanoparticle synergy, polymer interactions, wettability alteration, pH effects, salinity thresholds, and reservoir mineralogical compatibility. Detailed evaluations of experimental, numerical, and pilot-scale field studies are presented, offering a structured perspective on the mechanisms and practical conditions that govern LSW success. Emerging hybrid methods combining surfactants, alkali, nanoparticles, and polymers with LSW demonstrate measurable improvements in sweep efficiency, mobility control, interfacial tension (IFT) reduction, and tertiary recovery potential. Overall, this review provides an extensive synthesis of current trends, implementation challenges, and research opportunities for future EOR operations.