Hydrogen has only been recently recognized as a hydrate former, forming structure II hydrate (sII). In this communication, we report new experimental hydrate stability data for the binary hydrogen + water system at pressures ranging from (111.4 to 178.4) MPa and temperature down to 264.45 K. In addition, the formation and dissociation of so-called semiclathrates of hydrogen in the presence of tetrabutylammonium bromide (TBAB) were evaluated. The clathrate and semiclathrate dissociation measurements were conducted using a standard constant volume (isochoric) technique together with step-heating for achieving equilibrium conditions.