The present work conducts a detailed technoeconomic analysis of an environmentally friendly zero‐waste biorefinery process to valorize marine Ulva fasciata macroalgae into different sustainable value‐added products. The proposed sequential fully integrated process yielded 34.89% mineral‐rich water extract (MRWE), 2.61 ± 0.5% chlorophyll, 0.41 ± 0.05% carotenoids, 12.55 ± 1.6% starch, 3.27 ± 0.7% lipids, 22.24 ± 1.8% ulvan, 13.37 ± 1.5% proteins, and 10.66 ± 0.9% cellulose. The Aspen Plus software, utilizing the nonrandom two‐liquid (NRTL) model, was applied for process design, simulation, and technoeconomic analysis. Key findings include a positive net present value (NPV) of $49,755,544.90, a high return on investment (ROI) of 485%, and an internal rate of return (IRR) of 17%. The anticipated payback period is 7 years, indicating a quick recovery of the initial investment. These findings confirm that Ulva fasciata is a promising resource in the biorefinery industry, providing a viable and eco‐friendly alternative for the production of bio‐based products and a new market for seaweed‐based products.