The increasing demand for sustainable and eco-friendly agricultural practices has spurred interest in alternative substrates for mushroom cultivation. While lignocellulosic biomass and grains have been the traditional substrate of choice for producing mycelium and mushrooms. Here, we explore the use of micro- and macroalgae as a potential substrate due to their high nutritional content and ability to capture carbon dioxide (CO2) during their own life cycle. Using algae as a substrate for mushroom cultivation can provide a range of benefits. (1) microalgae can be produced in large quantities using cost-effective methods using raceway pond and photo bioreactors and macroalgae can be produced in the ocean. (2) Mycelium-based materials are typically produced from agricultural waste, which can be subject to supply chain issues; such as seasonality and availability; using seaweeds as substrate will help to overcome the problem ensuring a consistent and reliable supply of mycelium year around. (3) Algae can provide a rich source of nutrients for mushroom growth, including proteins, carbohydrates, and lipids, and can be broken down into simpler compounds by mycelium to be used as a food source. (4) Ability to produce carbon free mycelium and mushrooms since algae is a phototropic organism that uses CO2 from the atmosphere as carbon source and build their ow body mass. In other words, using algae as a substrate can help to reduce greenhouse gas (GHG) emissions associated with mushroom farming.