In continuation with the screening of biological properties of seagrasses, we isolated sulphated polysaccharides from Halodule pinifolia. This is the first report that indicates the presence of fucoidan-like H. pinifolia crude sulphated polysaccharide (HPCSP) that are commonly found in brown algae being present in marine angiosperms. Fucoidan-like structures such as β-mannuronic acid residues and sulphate groups were confirmed by Fourier transform infrared (FTIR) spectral analysis. There was a high content of uronic acid. The isolated HPCSP consisted mainly of total sugar (54.17%), protein (11.06%), carbon (18.25%), nitrogen (1.77%), hydrogen (3.62%), C/N ratio (2.04%) and uronic acid (2.61%). This isolated HPCSP was further investigated to determine anticoagulant and antioxidant activity. The HPCSP had high activity in the total antioxidant assay (125.86 mg ascorbic acid equivalents/g), DPPH radical scavenging rate (IC50 value 2.024 ± 0.12 μg/mL), deoxyribose radical scavenging rate (51.82% at 1000 μg/mL) and H2O2 radical scavenging rate (IC50 value 6.904 ± 0.34 μg/mL). In the anticoagulant assay, prolonged clotting time was observed with application of HPCSP with increasing concentrations. Further purification and characterization process is underway to confirm the structures of HPCSP. From the observed results, this fucoidan-like HPCSP could be developed as a new natural source of potential antioxidants in the functional food industry.