Biofouling from microorganisms, plants, barnacles, mussels or algae is a major problem for marine structures. Fouling leads to increased fuel costs due to increased frictional resistance on ships, and reduces reserve buoyancy of floating offshore structure, in addition to causing cage deformation and structural fatigue, impacting endurance of materials. The intrusion of invasive aquatic species (IAS) to new environments by ships is identified as a major threat to the world’s oceans. Marine fouling affects most manmade surfaces immersed in the sea, resulting in substantial losses. Anti-fouling paints tackle this problem to a certain extent. Extensive research is in progress in the antifouling technologies in maritime sector, with new products in compliance with International Maritime Organisation (IMO) regulations being developed. The most efficient solution to minimise fouling is to make surfaces unsuitable for settlers, coating them with Antifouling (AF) Paints containing toxic compounds. Most AF agents had Tributyltin (TBT), and has been phased out by IMO since 2008 due to harmful effect on environment.  However, use of TBT in AF paints is not prohibited, though has been restricted in several countries. The environmental problems by biofouling and toxicity of existing and alternative Anti-Fouling techniques are reviewed in this paper. Further, various ship hull cleaning technologies commercially available including afloat cleaning are also introduced. Keywords— Biofouling, TBT, Antifouling (AF), IAS, IMO, AFS, Alternatives