Locks, Canals and the Seaway
The engineering that turns five lakes and a river into one navigable route.
Get Free Great Lakes Cruise QuotesA Staircase for Ships
Lake Superior sits hundreds of feet above the Atlantic. Ships climb and descend that difference through a chain of locks, from the St. Lawrence Seaway near Montreal to the Welland Canal around Niagara Falls and the Soo Locks below Lake Superior. Lock size is also why Great Lakes cruise ships are small: anything sailing in from the sea must fit the Seaway’s chambers.
| Lock system | Where | What it does |
|---|---|---|
| St. Lawrence Seaway | Between Montreal and Lake Ontario | Lifts ships from the lower St. Lawrence to Lake Ontario around the river’s rapids |
| Welland Canal | Ontario, between Lake Ontario and Lake Erie | Eight locks lift ships about 326 feet, bypassing Niagara Falls |
| Soo Locks | Sault Ste. Marie, Michigan and Ontario | Carry ships between Lake Superior and Lake Huron |
The Great Lakes St. Lawrence Seaway site explains the Seaway and Welland systems and their seasons.
What a Transit Is Like
A lock transit is slow and quiet: the ship eases into a concrete chamber, gates close behind it, and water rises or falls until the next level is reached. On the Welland Canal the process repeats eight times, with Niagara’s escarpment visible along the way. Many itineraries combine the canal with a visit to Niagara Falls.
Frequently Asked Questions
How do ships get past Niagara Falls?
Through the Welland Canal in Ontario, which uses eight locks to lift or lower ships about 326 feet between Lake Erie and Lake Ontario.
What are the Soo Locks?
Locks at Sault Ste. Marie, on the St. Marys River, that carry ships between Lake Superior and Lake Huron around the river’s rapids.
Can I watch a lock transit from the ship?
Yes, and it is one of the highlights. The best views are usually from the bow or the top deck.
Canals Beyond the Lakes
The Erie Canal links the Hudson at Albany with Lake Erie at Buffalo, and the Rideau Canal joins Ottawa with Kingston on Lake Ontario. Both are covered on our sister site Waterways Cruising.
Locks and the Season
The lock systems close in winter, when ice makes navigation impossible, and reopen in spring. That is one reason Great Lakes cruising is a summer and autumn product. Commercial ships share the locks, so cruise schedules allow time for waiting; a transit can take longer than the timetable suggests, which is part of the charm for travelers who enjoy watching the big lake freighters at close quarters.
Cruise Through the Locks
Our cruise advisors at Mister Cruise will find itineraries with the lock transits and Niagara visits you want, free.
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