The waters of the Canadian Atlantic are considered to be some of the safest waters in the world in regards to shark attacks, despite the number and variety of shark species present. The most common  sharks in Canadian waters tend to be harmless, or are found offshore or in deep water. As well, cold water temperatures are present year round and relatively few people venture into the water compared to warmer climates. The result is that most sharks in Canadian waters are rarely encountered by humans, and those that are encountered tend not to be dangerous.

There are only a few species worldwide that are actually considered dangerous to humans, and none of those are regularly found in Canadian waters. The great white is considered very dangerous to people, but is extremely rare off Atlantic Canada (reported only about once every 5 years).  They are often caught accidentally, usually from becoming entangled in herring weirs or cod nets. However, great whites have apparently been involved in a few unprovoked attacks on small boats in the past off Nova Scotia and in the Bay of Fundy. One such attack occurred on July 2, 1932, about 16km northwest of Digby Gut, Bay of Fundy. In the early morning on a calm day a large shark attacked a fisherman and his son in their 7.6m motor-boat while they were hauling in their fishing gear. The shark bumped the boat repeatedly, working its way aft until it was clear of the boat . When inspected later on shore, they found the propeller blades bent, scrapes in the hull and a few teeth left embedded in the hull and keel. Upon examination of one of the teeth, the shark was determined to have been a great white around 4.6m in length. 

Another unprovoked attack occurred off Fourchu, Cape Breton in July of 1953. The boat was bitten and sank, dumping the two fishermen in the water. The shark did not attack the fishermen but one man drowned in his attempt to swim to shore. Again the attacking shark was identified by tooth fragments embedded in the hull. This shark was estimated to be 3.7m in length.

In the fall of 2000, a sea urchin diver encountered a shark while diving off Digby, Nova Scotia. The shark, apparently attracted by nearby lobster bait,  displayed some aggressive characteristics; bumping the diver, attempting to grab his catch bag and even hauling him several feet.  The diver was unharmed but the shark remained and circled him for a short time after. Judging by the description of the diver the attacking shark was probably a porbeagle shark.

In the summer of 2004, a father-son team fishing at a shark derby were admiring a blue shark which they had just caught and pulled up to the side of the boat. The boy attempted to lay his hand on the snout of the shark while it was in the water, trying to put it into a "trance" as he had seen done with great white sharks on TV. Apparently, the shark had not seen the same TV show, and it bit the boy's hand. Fortunately, only a few stitches were required. (NOTE: attempting to put your hand on the head of a live shark is NOT a good idea!).

Blue and whitetip sharks were implicated in attacks on injured people coming from torpedoed boats in the mid-Atlantic during World War II. Whitetip sharks have been known to be quite aggressive but blue sharks are not normally considered to be dangerous.  Greenland and mako sharks can grow large enough to attack a person, but have never been known to do so in Canadian waters.  All of the above species tend to be found in offshore waters rather than near shore.  Based on reports from other countries, most shark attacks tend to be associated with spear fishermen carrying bleeding and injured fish, or in the case of the great white, proximity to a seal colony.