It is shown that the energy of electronic minority charge carriers injected into an electrolyte from an illuminated semiconductor electrode may be significantly greater than that predicted by previous models. The time constants for tunneling from the semiconductor states in the depletion region are evaluated by two methods: approximating the final states as a continuum resulting from strong electron‐vibration interaction in the electrolyte, and calculating the oscillation time between semiconductor states and the discrete electrolyte states before vibrational relaxation. Comparisons are made with the time constants for intraband electronic relaxation in the semiconductor, including the effects of quantization due to confinement in the depletion region, and with those for the vibrational relaxation in the electrolyte. The general conditions for the injection of hot carriers from semiconductors into electrolytes are specified.