Auditory information transfer to afferent neurons relies on precise triggering of neurotransmitter release at the inner hair cell (IHC) ribbon synapses by Ca 2+ entry through Ca V1.3 Ca 2+ channels. Despite the crucial role of Ca V1.3 Ca 2+ channels in governing synaptic vesicle fusion, their elementary properties in adult mammals remain unknown. Using near-physiological recording conditions we investigated Ca 2+ channel activity in adult gerbil IHCs. We found that Ca 2+ channels are partially active at the IHC resting membrane potential (−60 mV). At −20 mV, the large majority (>70%) of Ca 2+ channel first openings occurred with an estimated delay of about 50 μs in physiological conditions, with a mean open time of 0.5 ms. Similar to other ribbon synapses, Ca 2+ channels in IHCs showed a low mean open probability (0.21 at −20 mV), but this increased significantly (up to 0.91) when Ca 2+ channel activity switched to a bursting modality. We propose that IHC Ca 2+ channels are sufficiently rapid to transmit fast signals of sound onset and support phase-locking. Short-latency Ca 2+ channel opening coupled to multivesicular release would ensure precise and reliable signal transmission at the IHC ribbon synapse.