Conditions
Scored by DiveConnect's site-physics model
Marine forecast via Copernicus Marine. Score is a rule-based guide from swell/wind vs. the site's exposure — always dive your own assessment.
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About this site
Lock 21 lies in the St. Lawrence River region of eastern Ontario, near the border with New York State, and is dived as a flooded canal structure with historic stonework typical of the area's lock sites. It reaches a maximum depth of around 20 metres and is rated an intermediate dive, with strong current a defining feature of the site and one that divers should plan for carefully. Some divers have also reported ocean sunfish passing through the area, though sightings like that are unusual for a freshwater canal site.
AI overviewMarine life here
Confirmed by our research team, reported by independent divers, or observed nearby via iNaturalist — each entry is labelled with its source.
Mola mola (ocean sunfish)Mola mola (ocean sunfish)Reported here · unconfirmed
Durable tips from divers — access, hazards, marine life, facilities. For day-of conditions, use the report tool in the conditions card above.
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