Abstract Yogurt was a product from pasteurized milk that fermented. The aims of this research was to examine the impact of seaweed addition during different storage lengths of time. on total lactic acid, viscosity, and syneresis tests of goat’s milk yogurt with Spirulina platensis. The completely randomised (CRD) factorial pattern (3 × 3), with three replications for each, was used in the research design. The addition of seaweed (0%, 5%, and 10%) was the first factor. The second factor was storage time (0, 8, 16 days). Analyse the data used the Analysis of Variance (ANOVA) and if a significant treatment effect was discovered used the Duncan test. The analysis showed no interaction (P>0.05) between adding seaweed and different storage times on total acids, viscosity, and syneresis. The addition of seaweed concentration significantly affect on viscosity, syneresis (P<0.05) but not significantly affect on total lactic acid (P>0.05). Storage time significantly affect total lactic acid, viscosity, and syneresis (P<0.05). Adding Spirulina platensis with a concentration of 5% seaweed and a storage time of 0 days showed the best results based on its quality, although up to the 16 day it still shows the feasibility of consumption.