Saint John Harbour is a coastal saltwater harbor located in the city of Saint John, New Brunswick. It is characterized by its active port and offers paddlers views of significant historical sites, including Partridge Island, a designated National Historic Site. The island features a distinctive lighthouse and the substantial concrete ruins of World War Two defensive positions, including observation towers, gun emplacements, and underground networks, which can be explored. The harbor's aesthetic is defined by a working waterfront juxtaposed with these historical elements. Paddlers can utilize the interconnected Harbour Passage trail system, which provides lookouts and access points connecting the north and west sides of the city to the uptown area. The area is served by local outfitters offering guided kayak tours, indicating it is a permitted activity. A primary paddling route involves a trip to Partridge Island, which allows for landing and exploration of its pathways and structures. The harbor is part of the larger Bay of Fundy coastal estuary system. Given the presence of an active commercial port, paddlers must be highly vigilant of significant boat traffic, including large vessels, and plan their routes accordingly to maintain safety. The conditions on the Bay of Fundy are known to change rapidly, with wind, fog, and rain giving way to clear, calm skies, so paddlers must be prepared for variable weather and water conditions.