As the global population is projected to reach 9.7 billion by 2050, the food industry faces a critical protein gap. Traditional livestock is environmentally unsustainable due to its high greenhouse gas emissions and excessive use of land. This review evaluates alternative protein sources, focusing on aquatic plants that offer a higher growth rate and nutritional value. It will also review the analysis of different extraction technologies and their suitability for different matrices. It explores chemical, mechanical, non-thermal and biochemical extraction methods as well as the green solvents that can replace the traditional toxic solvents. Notably, advanced systems like liquid biphasic systems (LBS) have demonstrated exceptional efficiency, achieving up to 99% protein recovery in aquatic matrices. While conventional alkaline extraction can yield recovery rates as high as 95%, its environmental impacts remain a concern. Emerging techniques, including microwave-assisted extraction (MAE) coupled with deep eutectic solvents (DESs), have reported protein yields of up to 91.7%. Therefore, this review highlights the importance of understanding extraction mechanisms and selecting appropriate technologies based on biomass characteristics and process objectives to enable sustainable protein recovery.