An adsorbent’s properties, its adsorption chemistry, and treatment efficiency are all interlinked for water/wastewater treatment. This critical review focuses on superadsorbents possessing ultrahigh adsorption capacities of ≥1000 mg g−1 for an efficient water/wastewater treatment. Using Google Scholar, we reviewed about 63 prominent studies (2017–2022) on superadsorbents to evaluate their preparation, characteristics, adsorption chemistries, and mechanistic interactions in the removal of aqueous inorganic and organic contaminants. The major contribution of this article is to present a series of perspectives on the potential upscaling of these adsorbents in real-scale water/wastewater treatment. The main findings are as follows: (1) the current literature analysis suggests that superadsorbents hold reasonable promise to become useful materials in water treatment, (2) there is still a need to perform extensive pilot-scale adsorption studies using superadsorbents under quasi-real systems representing complex real aqueous systems, and (3) the technoeconomic analysis of their upscaling in industrial-scale water/wastewater treatments still constitutes a major gap which calls for further studies. Moreover, the mass production and effective application of these superadsorbents are the major issues for real-scale water treatments.