<p>Smart textiles enable product development with interactive possibilities for textile and fashion design. Hydrochromic inks are colorants that change color when exposed to water and limited research has studied their integration in textiles and respective chromic behavior. The purpose of this work is to functionalize polyamide knitted fabric with hydrochromic ink, to characterize the thermal and fastness properties of the printed fabric and to discuss the mechanism by which the reversible hydrochromic ink performs reversible color change. Chromic behavior was studied using three different activation liquids, namely deionized water, sea, and pool water. Hydrochromic behavior showed that after activation, color return is influenced by ambient temperature, relative humidity as well as the liquid type which the colorant was exposed to. It was also observed that the hydrochromic ink reverts to its original color (white) and does not display significant changes in the predefined color after ten washing cycles.</p>