Algal biomass represents one of the most promising targets as a source of biofuel production, bioenergy, as sustainable feedstock and other valuable products. Algal biomass with its physicochemical properties and potential use has gained immense interest presently for converting it into biochar. Algal biochar synthesis has been done using conventional methods like pyrolysis, slow, and microwave-assisted methods along with modern ones like hydrothermal carbonization and torrefaction. Algal biochar has been variedly derived from the macroalga from fresh, brackish, and marine waters. This algal biochar has been extracted for maximum nutrient contents and capacity to exchange ions, as it is high in pH, ash, nitrogen sources, and inorganic components like phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). Biochar has been produced from fresh water macroalga Cladophora glomerata, as a biosorbent of heavy metals that have high toxicity. Other algal biochars include Chlorella vulgaris, Dunaliella salina, Haematococcus pluvialis, Gracilaria, and Oedogoniumsps has high affinity toward oxyanions like arsenic, molybdenum, and selenium that are difficult to be removed using conventional techniques. Algal biochar is a boon for amending soil for agricultural purposes especially applicable to acidic soils increasing the crop productivity and as absorbents for removing organic and inorganic contaminants in waste water treatment.