Superabsorbent polymers (SAPs) are cross-linked hydrophilic substances that can absorb and retain vast amounts of water or aqueous solutions. This review focuses on the current status of SAPs with a comprehensive review of the methods for synthesizing SAPs, SAP classifications, physicochemical properties, and SAP performance. Both traditional petrochemical SAPs and new bio-based SAPs synthesized from renewable sources were reviewed. SAP applications were reviewed in key areas including agriculture, hygiene, biomedical engineering, wastewater treatment, and drug delivery. Environmental considerations, biodegradability, and life cycle assessments (LCA) of SAPs, including end-of-life options such as composting and chemical recycling, were reviewed and discussed. Information concerning regulatory considerations, such as the EU Packaging Waste Regulation and US EPA Safer Choice, was presented as part of the discussion on sustainability and materials safety. Current issues in the field and potential future directions for the development of renewable, environmentally benign and functional superabsorbent materials were presented and discussed.