Full quantum statistical NVT simulation of the five-particle system H(3) (+) has been carried out using the path integral Monte Carlo method. Structure and energetics are evaluated as a function of temperature up to the thermal dissociation limit. The weakly density dependent dissociation temperature is found to be around 4000 K. Contributions from the quantum dynamics and thermal motion are sorted out by comparing differences between simulations with quantum and classical nuclei. The essential role of the quantum description of the protons is established.