High-resolution and airgun seismic-reflection mapping of the approaches to Esquimalt Harbour, Juan de Fuca Strait, reveal that offshore, sea-floor sediments consist of a widespread glaciomarine unit recognizable to the entrance of the strait. The upper part of the unit has been dated at approximately 10 000 radiocarbon years BP. An early postglacial sea-level low of at least −50 m appears to have formed a widespread unconformity. Nearshore sediments above the unconformity consist of sands, muddy fine sands, and minor gravel that were deposited in a prograding marine environment. Sediments have been accumulating off Esquimalt Harbour at a rate of approximately 1.9 cm per 100 years.