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Lake Ontario

The Routes

South-to-North swims

The traditional course follows the route used by 16-year-old Marilyn Bell on the first successful crossing of the lake which occurred on 8-9 September 1954. This route starts in the south at Niagara-on-the-Lake (NOTL) in the mouth of the Niagara River at Queen's Royal Park. The finishing point is 51.5 km away in a direction approximately NW (335°), through the first entrance in the breakwater to the west of Ontario Place, to finish at the wall along Aquatic Drive on Lakeshore Boulevard in Toronto. This finishing area is now known as Marilyn Bell Park (MBP).  Exit from the water is via a steel ladder; a series of these ladders are embedded in the wall approximately every 50 m along Aquatic Drive. 

As a measure of the challenge of this 51 km course, English Channel conquerors have taken an average of 50% longer to complete the Lake Ontario challenge - and a number of Channel Swimmers have failed in their attempts on Lake Ontario.

SSO only recognizes age, sex and speed records that are set over this course. 

Vicki Keith Point of the Leslie Street Spit (LSS; Toronto): The Leslie Street Spit, containing Tommy Thompson Park, extends into the lake east of the Toronto Islands. The rocky point, named Vicki Keith Point (VKP), has become a popular finishing point for cross-lake swimmers because the distance from NOTL to VKP is some 5 km shorter than the traditional route at 45.3 km and because it is the first possible mainland landing location after currents and winds push swimmers too far east to land at MBP. Landing at VKP can be dangerous as it is is composed of pieces of concrete and rebar. There is one relatively safe gravel beach located on the eastern side, some 330 m from the point. 

The small beach at the Boulevard Club is a slightly longer alternative to MBP when the breakwater at MBP is closed or the swimmer is blown too far west.


Clark Beach Park, Cherry Street (Toronto):  A lake crossing ending at the Clark Beach Park at the foot of Cherry Street passes a further 2.5 km beyond Vicki Keith Point into Toronto Port's Outer Harbour. It is shorter than the traditional course to MBP.

Finishes in Toronto at MBP, Clark Beach park, or The Boulevard Club are all within the bounds of the Port of Toronto and require written permission from the Port. Finishes at the Leslie Street Spit or Humber Bay Park West are not within the Port or Toronto.

North-to-South Swims 

Due to the strong current flowing out of the Niagara River and the Welland Canal, North-to-South swims general finish in the area of Port Dalhousie, most popularly the beach just to the west of the Port Dalhousie piers. 

Oakville Swims

There have been 4 Lake Ontario crossings between Oakville and Port Dalhousie. These are 41-42 km in length and can be quite difficult due to the unpredictable currents and temperatures near Oakville.

Eastern Lake Ontario swims

There have been 5 swims at the eastern end of Lake Ontario from New York State to Kingston, Ontario ranging in distance from 33 to 59 km.


Lake Ontario Challenges


There are significant currents in Lake Ontario and their speed and direction vary depending upon: proximity to rivers, and the present and recent wind speed and direction. The currents can slow the swimmer down or push them off course even in the middle of the lake.

Surface wind-driven circulation currents in Lake Ontario generally travel counter-clockwise (see Figure 1). 

  • Within about 3 miles of the Niagara shore, currents will likely move to the east at 0.3 to 0.6 knot (0.6 to 1.1 km/h) with a maximum of 1 knot (1.9 km/h). 

  • Beyond about 5 km, the current will become more northerly and weaker, until near the centre of the lake where the direction may be variable and the speed modest. The currents then reverse towards the west and strengthen.

  • Within about 8 km of the Toronto shore, currents will likely flow to the southwest at 0.3 to 0.6 knot (0.5 to 1.1km/h) with a maximum of 0.8 knot (1.5 km/h).

  • At least one day of strong winds from the north or northeast is usually required to reverse the above pattern (see figures 2 & 3).

The Niagara River current enters Lake Ontario at speeds of 2 - 4 knots (4 - 7 km/h) and slows to about 0.4 knot (0.7 km/h) approximately 5 km offshore. The current will push the swimmer in a north-westerly direction. To gain the maximum advantage from this current, it is advantageous to allow the swimmer to be pushed slightly west of the straight-line course to Toronto.  This manoeuvre can also provide a favourable position to manage any north-westerly winds or the Humber River current. The course can be slowly corrected as the swim progresses.

There is a shallow area, about 300m long, in the mouth of the Niagara River on the Canadian side called the Niagara sandbar where the waves can suddenly become huge and choppy. This can be upsetting to swimmers as they enter the lake.  


On the Toronto side, the Humber River creates a current moving from the mouth of the river southeastwards at a speed up to half a knot (1 km/h) into the lake for about 6 -12 km, then reversing to flow westwards along the shoreline. Swimmers have to have enough endurance and speed near the end of their swim to be able to breakthrough this current. 


There is also a significant flow out of the Welland Canal, and Port Dalhousie (12 Mile Cr).

The Tides and Currents division of the National Oceanic and Atmospheric Administration provides a nowcast and 3 day forecast of the currents on Lake Ontario (see diagram).

Water Temperatures 

The temperature of Lake Ontario can vary widely depending upon location in the lake and the wind direction in the preceding days. Northwest winds after the passage of a cold front can quickly push the surface water on Lake Ontario towards the southeast shore and bring much colder water up from deeper layers to the surface (upwelling) along the northwest (Toronto) shore. This effect can result in a surface temperature of 22°C in Niagara dropping to 10°C in a matter of hours as the swimmer approaches Toronto.

The Great Lakes Coastal Forecasting System website provides a nowcast and 5 day forecast for wind, waves, and surface water temperatures for all Great Lakes (see diagram).

Lake Ontario is generally warm enough to swim starting the last week in July and ending in the second week of September. 

Lake Ontario Data

Cross-Lake Distances

Niagara-on-the-Lake (NOTL) - Marilyn Bell Park, Lakeshore Boulevard, Toronto = 50.5 km

NOTL - Humber Bay Park West= 51.0 km

NOTL - Boulevard Club (beach to the east) = 51.7 km

NOTL - Clark Beach Park (Foot of Cherry Street) = 47.8 km

NOTL - Vicki Keith Point, Leslie Street Spit = 45.3 km

​Port Dalhousie (Beach west of the harbour entrance) - Marilyn Bell Park = 48.8 km

Port Dalhousie - Marie Curtis Park = 47.7 km

Port Dalhousie - Viki Keith Point = 45.5 km

Port Dalhousie - Coronation Park, Oakville = 41.3 km

Lake Ontario Landmarks

Southern Locations

Niagara-on-the-Lake: 43° 15' 27"N; 79° 04' 06"W

Port Dalhousie Beach to west of harbour:  43° 12' 19"N; 79° 15' 53"W

Northern Locations

Marilyn Bell Park, Lakeshore Boulevard: 43° 37' 48"N; 79° 25' 39"W

The Boulevard Club, Beach to the east: 43° 38' 06"N; 79° 26' 31"W

Vicki Keith Point, POINT: 43° 36' 46"N; Leslie Street Spit 79° 20' 39"W

Vicki Keith Point, BEACH: 43° 36' 55"N; Leslie Street Spit 79° 20' 34"W

Clark Beach Park, Foot of Cherry Street: 43° 38' 06"N; 79° 20' 46"W

Humber Bay Park West: 43° 36' 50"N; 79° 28' 45"W

Oakville, Coronation Park: 43° 24' 27"N; 79° 41' 28"W

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