Hydrogels, characterized by a three-dimensional cross-linked network of hydrophilic polymers, possess the capacity to absorb and hold substantial quantities of water. They show significant potential for applications in both biomedical and engineering domains. Calcium cross-linked alginate (Ca-alginate) hydrogels exhibit various excellent characteristics, including biocompatibility, biodegradability, high hydration, and ease of production; thus, they have been widely utilized in the biomedical field. Moreover, this class of hydrogels has also recently been recognized as a promising alternative to conventional plastics for aquatic applications, aiming to reduce environmental pollution and dependence on fossil fuels. In this research, strong, stiff, and tough Ca-alginate hydrogels are developed via a drying and reswelling technique. The variations in the mechanical characteristics of the hydrogels caused by varying drying temperatures during the fabrication process are evaluated. The obtained results demonstrate that the hydrogel prepared using this technique with a drying temperature of 90 °C displays excellent mechanical performances, which are comparable to various commonly used traditional plastics. Furthermore, the effective application of the hydrogels was successfully demonstrated. With these features, the developed hydrogels hold promise for various fields.