Different hydrating cosmetic creams were formulated with ulvans obtained by a previously optimized process, consisting of hydrothermal treatment and a solvent-free concentration stage to obtain ulvans with 80% purity in carbohydrates, 34% rhamnose, 11% sulfate and >10 kDa. The incorporation of low-mineralization thermal spring waters in the formulation of hydrating creams with 1% ulvans and green ingredients caused a shear thinning behavior that was more marked than in creams formulated with distilled water. As Burgas thermal spring water caused the largest decay, suggesting an improvement in the cream’s spreadability on the skin. This spring water was selected for formulating and bottling a commercial hydrating cream that was further evaluated regarding both physicochemical and biometric properties with a group of 120 healthy volunteers to assess the performance of both ulvans and As Burgas thermal spring water. The results of both objective and subjective evaluation indicate the enhanced skin hydration provided by ulvan and thermal spring water, as well as their favorable additive effect. A high tolerance was observed because all tested creams decreased the tightness sensation, and scaling was significantly reduced in the ulvan group. The findings confirm the potential additive skin benefits of combining ulvan with thermal spring water in hand cream formulations.