Short Sea Shipping in Canada

Updated 2026-11-10

Short sea shipping is the carriage of cargo and passengers by water over relatively short distances, normally along a coast or on inland waterways, without an ocean crossing. In Canada the term mostly applies to the Great Lakes and St. Lawrence corridor, to coastal runs in British Columbia and Atlantic Canada, and to northern resupply. It is closely linked to the idea of a "marine highway", a waterway treated as a freight route that complements roads and railways.

This page covers what the term means, how it fits Canadian geography, which cargoes and ports are involved, how water transport compares with trucks and trains, and what the policy setting and statistics show.

What short sea shipping means

Short sea shipping is the movement of goods by sea along a coast or between nearby ports, as opposed to deep-sea or intercontinental shipping. Related phrases include "marine highway" in North America and "motorways of the sea" in Europe. The European Commission defined it as the movement of cargo and passengers by sea between ports in geographical Europe, and the definition also reaches feeder services, islands, rivers and lakes. Inland navigation between cities on a river is a separate idea, although the two overlap in practice.

The ships involved are small by ocean standards. Typical vessels run from about 1,000 to 15,000 deadweight tonnes and draw roughly 3 to 6 metres of water. That size lets them call at shallow or modest ports that large ocean carriers cannot use. The cargo mix is wide: grain, fertilizers, steel, coal, salt, stone, scrap, minerals, oil products, containers and passengers.

No single Canadian statute defines short sea shipping. The expression appears in policy discussion, industry material and studies, and its edges vary. Some definitions stress the coastal and domestic leg of a longer chain, and others include cross-border trade between Canada and the United States on the Great Lakes.

The Canadian setting

Canada has Pacific, Atlantic and Arctic coasts and a large inland waterway connecting the Atlantic to the middle of the continent. The Great Lakes-St. Lawrence Seaway system is described by its operators as a marine highway extending 3,700 km from the Atlantic Ocean to the Great Lakes. Measured to specific ports, the distance from the Atlantic to Duluth, on Lake Superior, is 2,340 miles (3,770 km), and to Chicago, on Lake Michigan, 2,250 miles (3,620 km). Lake Superior sits 601 feet (183 m) above sea level, and locks lift or lower vessels along the way.

Transport Canada's marine chapter in Transportation in Canada 2011 divides domestic marine activity into four regions.

• The Pacific coast has a large fleet engaged in barging and towing, along with the ferry network operated by B.C. Ferries.
• The Great Lakes and St. Lawrence region has operators carrying dry and liquid bulk cargo. The report names Fednav, Algoma Central, Canada Steamship Lines and Groupe Desgagnés among the key carriers.
• The Atlantic region includes container service to Newfoundland, oil platform resupply and inter- and intra-provincial ferries.
• The northern region relies on marine transport for community resupply and resource development. The eastern Arctic sealift runs from Churchill and Montreal, and the western Arctic has its own operator.

The same report states that short sea shipping occurs in the St. Lawrence and Great Lakes, off the British Columbia coast and in the North.

The Great Lakes and St. Lawrence corridor

The St. Lawrence Seaway opened in 1959, after construction that began in 1954. It runs 370 miles (600 km) between Montreal and Lake Erie and has 15 locks, 7 on the St. Lawrence River and 8 on the Welland Canal. Construction cost C$470 million, of which C$336.2 million was paid by Canada. The locks measure 766 feet long, 80 feet wide and 30 feet deep, and the largest ship that fits is 740 feet long and 78 feet wide, a size known as Seawaymax. Only about 10 percent of oceangoing ships can pass through the whole system.

Channel depth varies along the route: 41 feet (12.5 m) downstream of Quebec City, 37 feet (11.3 m) to Montreal and 27 feet (8.2 m) upstream of Montreal. These limits keep the corridor in the size range associated with short sea tonnage. The Poe Lock at the Soo Locks measures 1,200 feet by 110 feet, far larger than the Seaway locks, so the biggest lake freighters work only above the Welland Canal.

Navigation is seasonal. Shipping on the Great Lakes usually stops for two to three months in winter, after icebreakers keep the passage open through the fall and early winter. Transport Canada reported a record 284-day Seaway season in 2011, from March 22 to December 30. At the end of 2023 the operators described the longest scheduled season in the system's history: the Montreal-Lake Ontario section closed on January 5, 2024 and the Welland Canal on January 7.

Two bodies manage the binational system. The St. Lawrence Seaway Management Corporation, a not-for-profit corporation established in 1998 under the Canada Marine Act, operates the Canadian assets, which remain the property of the Government of Canada, under a long-term agreement with Transport Canada. The U.S. Great Lakes St. Lawrence Seaway Development Corporation covers the American locks.

Cargo and commodities

Bulk cargo dominates water transport in Canada. Transport Canada's 2011 chapter says bulk cargo, largely natural resources, is the largest share of port traffic by tonnage. Major exports are iron ore, petroleum products, coal and grain, and major imports are petroleum products, minerals and coal. The containerization rate was 11.6 percent overall in 2010.

The Great Lakes follow a similar pattern, with ore, grain and coal as the main cargoes of lake freighters. The 2023 results published by the Seaway operators give a recent picture of the whole system, which handled nearly 38 million tonnes that year, up more than 3.4 percent from 2022.

The operators also reported fewer transits in ballast and an additional 1.2 million tonnes of cargo. These totals cover all traffic through the Seaway, domestic and international, so they are wider than short sea shipping in the narrow sense.

Short sea operations also serve niche flows. One example is a tug and barge combination moving aluminum ingots 944 nautical miles (1,748 km) from Quebec to Ohio. Another is a winter service with a European-built vessel under the Canadian flag between Halifax and Saint-Pierre et Miquelon in 2008 and 2009.

Ports

Canada's largest ports are administered as Canada Port Authorities, and Transport Canada oversaw 17 of them at the time of its 2011 report. In the Great Lakes and St. Lawrence region the major ports named in reference material are Bécancour, Hamilton, Montreal, Quebec City, Trois-Rivières, Thunder Bay, Toronto and Windsor. Montreal is the leading container port in the region, with 1,288,910 TEUs recorded for 2006.

On the American side of the lakes, the Great Lakes Waterway reference names Duluth-Superior, Chicago, Detroit, Toledo, Cleveland and Two Harbors.

The 2011 report states that Canada Port Authorities handled 269 million tonnes in 2010, or 69 percent of the tonnage at all Canadian ports. Port authorities therefore account for most traffic, and a port's role in short sea shipping depends on whether it has the depth, terminals and inland connections for small and mid-sized vessels.

Domestic marine traffic in numbers

The most recent official split of domestic traffic used for this page comes from Transport Canada's 2011 report. Canadian marine freight reached 392 million tonnes in 2010, up 10 percent from 2009. Domestic flows accounted for 58 million tonnes, transborder traffic with the United States for 103 million, and other international traffic for 231 million. Domestic traffic is the smallest of the three categories.

Foreign participation in the coasting trade ranged from 1.2 percent to 11.1 percent of total tonnage carried between 2000 and 2010. Most temporarily imported vessels were tankers and special-purpose offshore vessels. Foreign-registered ships carried about 99.9 percent of Canada's deep-sea (non-U.S.) cargo.

The same report puts the Quebec marine industry at $3 billion in annual activity, citing a study by SODES and the Quebec transport ministry. At system level, the 2023 press release states that shipping through the Seaway supports over 329,000 jobs and CAN$59 billion in economic activity in Canada and the United States.

Comparison with road and rail

Short sea shipping competes with trucking and rail for some freight and relies on them for the rest. The documented Canadian evidence comes mostly from individual projects.

Capacity per trip

A single vessel replaces many trucks. The aluminum ingot service is said to put the load of one barge at the equivalent of 220 forty-tonne trucks. A Transport Canada case describes woodchips carried by barge along the North Shore to a mill at Trois-Rivières from April 2005 to June 2007. The service removed an estimated 18,000 heavy-truck trips per year from highways 138 and 40.

Emissions and road wear

In that case Transport Canada estimated a reduction of 9,000 tonnes of greenhouse gas emissions per year and road maintenance savings of $350,000 per year. These figures come from a single Canadian project and do not amount to a nationwide comparison of modes.

Limits and trade-offs

Water transport has constraints that explain why it carries only a share of freight.

• Goods bound inland still need to be transferred and delivered by truck or rail, which adds handling steps.
• Ships serve fixed ports, while trucks offer door-to-door service.
• The Seaway and the upper lakes close for part of the winter.
• Lock dimensions cap vessel size on the lower system, and the 27-foot channel above Montreal limits draft.
• Terminal capacity, port access and inland connections have to exist at both ends.

Wikipedia's transport overview observes that roads are the dominant mode for both passengers and freight in Canada, with trucking producing 35 percent of transport GDP against 25 percent for rail, water and air combined. Those shares show the scale of the modes short sea shipping works alongside, though they are not a like-for-like volume comparison.

The Transport Canada report also records a feasibility study by St. Lawrence ship operators, with the Quebec transport ministry and Hydro-Québec. It found a truck-ship-truck service to North Shore shipyards technically and economically viable, while noting that logistical, economic and social challenges remained.

Policy context

The Seaway operators promote the system through the binational Hwy H2O initiative, which the 2024 release says aims to increase use of the system and the volume of marine cargo shipped. The same release calls the Seaway an essential component of a Green Shipping Corridor, which both corporations planned to develop further from 2024.

Several other elements shape the market.

• Transport Canada reports that foreign vessels carried between 1.2 and 11.1 percent of coasting-trade tonnage in the 2000 to 2010 period, which shows how much domestic trade is open to temporarily imported ships.
• Transport Canada's 2011 chapter says a gradually decreasing fleet-average sulphur limit for Great Lakes vessel operators was planned from 2012 to 2019, with vessel-level Emission Control Area standards starting in 2020.
• The Seaway system recorded asset renewal expenditures of $49.3 million in 2010-11, according to the same report, as part of the upkeep of the Canadian locks.
• An expansion plan for the Seaway was scrapped in 2011 for budgetary reasons, according to the Saint Lawrence Seaway reference, so the dimensions of the 1959 system still apply.

Abroad, the European Commission and the European Green Deal have made short sea shipping a transport policy priority. Wikipedia reports that roughly 40 percent of freight moved in Europe travels by short sea shipping, and that the Green Deal sets targets of raising inland canal and short sea shipping by 25 percent by 2030 and 50 percent by 2050. The United States promotes the concept through America's Marine Highway program. These targets and instruments are not Canadian.

Frequently asked questions

What is short sea shipping?

It is the carriage of cargo or passengers by water over short distances, usually along a coast or on lakes and rivers, without crossing an ocean. The ships are typically between about 1,000 and 15,000 deadweight tonnes.

Where does short sea shipping take place in Canada?

Transport Canada states that it occurs in the St. Lawrence and Great Lakes, off the British Columbia coast and in the North. The Great Lakes and St. Lawrence corridor, about 3,700 km long, is described by its operators as a marine highway.

What cargo moves on the Great Lakes and St. Lawrence?

Mostly bulk goods. In 2023 the Seaway system handled nearly 38 million tonnes, including 10.4 million tonnes of grain, more than 12 million tonnes of dry bulk such as potash, gypsum, cement and stone, and 3.6 million tonnes of liquid bulk. Iron ore and coal are also among the main cargoes of the lakes.

How large can a ship be in the Seaway?

The maximum is 740 feet long and 78 feet wide, a standard known as Seawaymax. The locks are 766 feet long, 80 feet wide and 30 feet deep. Larger lake freighters operate above the Welland Canal, since the Poe Lock at Sault Ste. Marie is 1,200 feet by 110 feet.

How does short sea shipping compare with trucking?

A Quebec barge service for woodchips removed an estimated 18,000 heavy-truck trips per year and cut 9,000 tonnes of greenhouse gas emissions annually. Against that, goods still need truck or rail at the ends of the trip, ports are fixed, and the Seaway closes in winter.

How much domestic marine traffic does Canada have?

In 2010 Transport Canada reported 392 million tonnes of marine freight in total, of which 58 million tonnes was domestic, 103 million transborder and 231 million other international.

When is the Seaway open?

The season is set each year. In 2011 it ran for a record 284 days, from March 22 to December 30. The 2023 season was the longest scheduled in the system's history, with the Montreal-Lake Ontario section closing on January 5, 2024 and the Welland Canal on January 7.