The development of low-cost, efficient, and stable electrocatalysts is urgent in sustainable energy devices. Bifunctional catalysts are particularly crucial because they surmount the kinetics limitations stemming from the sluggish mechanism associated with hydrogen evolution reaction (HER)/oxygen evolution reaction (OER) in water electrolysis. Herein, self-supporting highly branched urchin-like NiCoP/NiFeP heterostructures were in situ grown on Ni foam (NF) through hydrothermal and phosphorization treatments, as examined by a set of characterizations. The role of the compositions played within the material was rigorously investigated to maximize the catalytic properties, coupled by elaborating the catalytic mechanism. The optimized NiCoP/NiFeP/NF exhibited superior performance with the boosted HER activity (overpotential of 43 mV @ 10 mA cm