<p>Hydrogels have been widely used in tissue engineering and biomedical applications owing to their high water content and tunable functionality. Nevertheless, high water content and loosely cross-linked networks restrict the mechanical properties of hydrogels and their practical applications. Herein, we present a facile approach for designing strong and tough bacterial cellulose/poly(vinyl alcohol) (BC/PVA) double-network hydrogels involving immersing BC into PVA solutions and then freezing-thawing. The PVA chains encapsulate the BC nanofibers through hydrogen bonding interactions and chain entanglement, infiltrate the fibrous network, and thereby enhance the densification of the BC/PVA hydrogel. Concurrently, repetitive freeze-thaw cycles facilitate the regulation of PVA chain conformation and promote PVA crystallization, which increases the rigidity of the PVA segments. The resulted hydrogel demonstrates an exceptional tensile strength of (2.13±0.03) MPa, a remarkable toughness of (1.15±0.03) MJ·m⁻³, and a high water content of up to 95%. Furthermore, the double-network hydrogels exhibit excellent biocompatibility. This study offers a practical strategy for the design of robust and tough hydrogels with potential utility in biomedical applications.</p>