Abstract: Porous carbons with well-developed pores, tunable microstructures and stable chemistry play a significant role in energy storage and environmental pollution control. Biomass is a carbon precursor that is abundant, low cost, sustainable and carbon neutral, and is promising for the large-scale production of porous carbons. Among the various types of biomass, algae usually contain abundant cellulose and heteroatoms, which are suitable precursors for heteroatom-doped carbons. Recent advances in synthesis methods for algae-based porous carbons are reviewed and their pore formation mechanisms discussed. Their potential applications in adsorption, catalysis and energy storage are highlighted, and strategies for improving their performance are proposed. Future research trends and challenges for algae-based carbons are discussed, especially as they relate to their low-cost production and performance improvement.