The causeway completely blocks the Strait of Canso, which links the waters of St. George's Bay in the Northumberland Strait, a sub-basin of the Gulf of St. Lawrence, with Chedabucto Bay on the Atlantic Ocean.

It has a single Seawaymax lock to account for tidal differences; any vessel capable of transiting the St. Lawrence Seaway will fit through the Canso Canal.

The Canso Canal Bridge is a 94-metre-long (308 ft) swing bridge which carries the Trans-Canada Highway and a railway line across the canal immediately south of the southern end of the lock.

Vessels entering St. George's Bay to the west of the canal, or Chedabucto Bay to the east, must comply with a Vessel Traffic System operated by the Canadian Coast Guard.

About 85 per cent of vessel traffic is owned or operated by shipping companies, fishermen and government, the remainder being pleasure craft users.