Polyoxometalate (POM)-based binary and ternary hybrids, including combinations of POMs, semiconductors, nanostructured carbon (carbon nanotubes, graphene, carbon dots, etc.), and metal nanoparticles (MNPs), are key materials in photoelectrocatalysis. POM plays a key role in the construction of nanohybrids and contributes to their photoelectrochemical catalytic properties. These composites combine the properties of two or three functional nanoscale materials, resulting in a wide range of applications, including catalysis, energy conversion and storage, molecular sensors, and electronics. Herein, we summarize the latest progress in POM-based binary nanohybrids (POM/metal, POM/semiconductor, and POM/nanocarbon) and ternary nanohybrids (metal/POM/nanocarbon), particularly in energy materials for photocatalysis, fuel cells, biosensors, and photoelectrochemical devices. Current applications are critically assessed, and promising target systems are discussed.