Comprehending hydrogen diffusion and trapping in high-purity aluminum is a needful step toward knowing hydrogen interactions in aluminum alloys. Despite several investigations into the diffusion of hydrogen in solid aluminum, there is little agreement on the activation energy and frequency factor. Experimental methods to induce the diffusivity in aluminum are thickened by the low solubility of hydrogen and by the absence of knowledge of hydrogen microstructure interactions. Though a number of researchers realize that hydrogen may be trapped at lattice defects such as dislocations and vacancies, little work has been done to quantify the effects of microstructural trapping on hydrogen segregation and transport in aluminum and aluminum alloys. The aim of this chapter is to define the activation energy and frequency factor for hydrogen diffusion through the aluminum lattice and to quantify the hydrogen trap states present in high-purity, polycrystalline aluminum. Despite wide research, there remain unsolved questions concerning hydrogen’s behavior in aluminum, particularly its site preference, solubility, and diffusion properties.