Water hyacinth (WH), is one of the world's most intractable and invasive weed species. Recent studies explored the efficacy of this species as a biochar (BC) in improving soil fertility and metal adsorption. However, the soil water retention (SWR) property and crack potential of soil-WH biochar composite has still not been studied. The major objective of this study is to investigate the SWR property and corresponding crack intensity factor (CIF) for compacted soil-WH BC composites. Soil-WH BC composites at five percentages (0, 2, 5, 10 and 15) was compacted and soil parameters such as suction (Psi), water content and CIF were simultaneously monitored for 63 days (including 9 drying-wetting cycles). Results showed that soil-WH BC composite at all percentages retains more water (max. 19% and min. 6.53%) than bare soil at both saturated and drought conditions. Gradual inclusion of WH BC to soil decreases the CIF potential from 7% to 2.8%.