Scuba diving in the St. Lawrence river

Scuba diving in the St. Lawrence river, specifically the stretch between Kingston and Montreal, doesn’t seem obvious from above the surface. But with a long history as a shipping channel, there are numerous historic shipwrecks all along the river that make for some very interesting dives. Many wrecks have been underwater for more than 100 years!

All these dive sites can be visited with Abucs Scuba charters from the Dive Brockville Adventure Centre. Some charters depart from Brockville, while others depart from Rockport (30 minutes west of Brockville). They run 2 charters per day with a fleet of 5 boats, from April to December. Tell them we sent you! (They also offer dive charters in Lake Ontario near Picton.)

Henry C. Daryaw wreck

The Henry C. Daryaw was a large 219-foot steel freighter built in 1919 and sank in 1941 after striking a shoal. It sits perfectly inverted in 27 meters of water, with the large fatal gash is clearly visible. Ropes are used to pull yourself upstream, drift downstream and repeat.

The large twin propellers and the rudder are still intact.

The current is strong, so ropes are installed to pull yourself against the current. Then go with the flow and drift over the hull, where you can see the gash that sunk the ship. Repeat a few times because the drifting can be quite fun.

Lillie Parsons wreck

The Lillie Parsons was a 131-foot double-masted schooner with a retractable centreboard built in 1868 and sank in 1877. It lies upside down on the side of Sparrow Island, in quick current. You’ll stay tightly glued to the descent line, and use chain laid along the wreck to pull yourself upstream.

While you could follow the mooring line back to the surface, most divers choose to end the dive with an exhilarating drift. You make your way to the stern and start drifting in the current. If you maintain a depth of 12 meters and stay close to the island wall, you’ll eventually see a rope leading to the surface. Follow the rope to complete your safety stop. While it seems daunting when you’re briefed, it’s actually quite achievable, even for newer divers.

Robert Gaskin wreck

The Robert Gaskin was originally a 113-foot double-masted wood barge built in 1863. Over its history, it sank, was salvaged, converted into a steam-powered cargo barge, sank again, salvaged again, and finally sank for a third and final time. It sits in 15-20 meters of water and is suitable for newer divers, not far from downtown Brockville.

A.E. Vickery wreck

The Vickery schooner was built in 1861 and launched as the J.B. Penfold, and renamed in 1884 before sinking 1889. The wreck starts at 20 meters and goes down to 35 meters.

The deck railing is still in excellent condition and the windlass sits proudly at the bow.

Keystorm wreck

The Keystorm was a steel steamer built in 1908 carrying 2230 tons of coal when it sank in heavy fog in 1912. It sits on its starboard side with its bow at 6 meters and stern at 35 meters. The cargo was salvaged, but they were unable to salvage the Keystorm (cables from the efforts are still visible).

The Keystorm is a large wreck at 256 feet in length. The cargo holds are stunningly large. Because of its size and depth, a few dives are really required to do the wreck justice. It can get dark at depth, so an underwater torch is handy to appreciate this wreck. The superstructure is in shallower, brighter water, so it’s easy to explore for divers who want to stay shallower.

This is one of my favourite wrecks in the St. Lawerence river.

America wreck

The America is a drill barge that sank in 1932, sitting upside down in about 20 meters of water. One of the main features is the four large support legs used while drilling.

The America wreck is often combined with a charter to the Keystorm, as they are located very close together. The America is situated in the shipping channel, so you descend a mooring line just outside the channels, and swim a short distance along the river bottom to the wreck. Because of it’s location in the shipping channel, it’s considered an advanced dive since you cannot safely ascend directly above the wreck.

Kinghorn wreck

Another of my favourite wrecks, the Kinghorn (sometimes spelled Kingshorn) is a relatively plain 130-foot schooner-barge with plenty to offer to divers. It sank in 1897 and sits upright at depths of 25-30 meters.

The original ship wheel and windlass are proudly on display. Some simple penetration through the cargo holds is possible if you’re careful not to disturb the silt.

Ash Island barge

This wreck got its name because it was a belly dumper barge that sank on the edge of Ash Island in the Thousand Islands area. Some sources say it was scuttled after completing its work. It has 3 holds still full of rock. It’s a deep dive, starting around 25 meters and going down to 35+ meters, with even greater depths possible past the wreck. Consider diving on air to explore the deeper sections. Also a great dive site for deep or technical training/exploration.

You complete your safety stop while drifting alongside the Ash Island wall, which is overflowing with bright white mollusc shells.


While the century-old wrecks are impressive, there are some challenges with scuba diving in the St. Lawrence river…

Water temperature

Scuba diving in a temperate location generally means very cold water. But in the summer, the flow mixes the warmer surface water with the colder deeper water, making for quite comfortable diving temperatures with no thermocline.

During the summer months, water temperatures hit 20-24°C/68-75°F, so a single-layer 7mm wetsuit is more than sufficient. Drysuits will help extend the season. Hoods are optional for extra warmth. Gloves are recommended for protection (although not strictly necessary), because most underwater surfaces get covered with sharp zebra mussels.


As a river, there is a good current which can get quite strong at some dive sites. The St. Lawrence river has a flow rate of 16,800m3/s, ranking it #14 for highest discharge of the world’s rivers.

At some wrecks, the current is so strong that it’s impossible to swim against it, and ropes have been installed to help pull yourself against the current. It’s also a good idea to dive with a surface marker buoy (safety sausage) in case you get pulled away by the current.

So ditch your flexible warm-water fins, and opt for stiffer plastic or rubber technical fins, like the Mares Avanti Quattro+ or the Apeks RK3 fins.


The other downside of a river with high flow is the lower visibility, particularly in the summer from suspended algae. It can vary randomly between dive sites and over time. Some dives can have amazing visibility, while others rather poor.

Share your favourite experiences scuba diving in the St. Lawrence river in the comments below. What are your favourite wrecks?

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