Marathons in Ontario 2027

17 marathons and 5 half marathons coming up in Ontario, by date. Rated races show how many minutes the course adds or saves against an average road race, from its climbing, surface and typical race-day weather.

Flattest marathons in Ontario

Rated road races, least total climbing first.

1.Niagara Falls MarathonNiagra Falls, 42m climbing, -8 min vs average, Oct 2027
2.Toronto Waterfront MarathonToronto, 57m climbing, -8 min vs average, Oct 2027
3.Georgina Spring Fling MarathonGeorgina, 69m climbing, -7 min vs average, May 2027
4.Georgina MarathonGeorgina, 69m climbing, 0 min vs average, Sept 2027
5.Hamilton Marathon Road2HopeHamilton, 81m climbing, -6 min vs average, Nov 2027
6.Toronto MarathonToronto, 94m climbing, -8 min vs average, May 2027
7.St. Lawrence MarathonCornwall, 138m climbing, -6 min vs average, Apr 2027
8.Muskoka MarathonHuntsville, 183m climbing, -1 min vs average, Oct 2027
9.Beneva Mississauga MarathonMississauga, 187m climbing, -4 min vs average, Apr 2027
10.Ottawa MarathonOttawa, 201m climbing, +3 min vs average, May 2027

Flattest half marathons in Ontario

Rated road races, least total climbing first.

1.Niagara Falls Half MarathonNiagara Falls, 30m climbing, -4 min vs average, Oct 2027
2.Mississauga Half MarathonMississauga, 45m climbing, -4 min vs average, Apr 2027
3.Toronto Waterfront Half MarathonToronto, 61m climbing, -3 min vs average, Oct 2027
4.Forest City Road Races Half MarathonLondon, 134m climbing, +2 min vs average, June 2027

Marathons in Ontario (17)

Apr 2027

St. Lawrence Marathon

-6 min

Cornwall, Ontario

25 Apr 2027Road138m gainFull

Beneva Mississauga Marathon

-4 min

Mississauga, Ontario

25 Apr 2027Road187m gainFull

May 2027

Toronto Marathon

-8 min

Toronto, Ontario

2 May 2027Road94m gainFull

Georgina Spring Fling Marathon

-7 min

Georgina, Ontario

2 May 2027Road69m gainFull

Ottawa Marathon

+3 min

Ottawa, Ontario

23 May 2027Road201m gainFull

23 May 2027 Sudbury Rocks Marathon, Sudbury, Ontario

June 2027

20 June 2027 Community Strong Weekend Marathon, Sault Ste. Marie, Ontario
20 June 2027 Niagara Ultra Races Marathon, Niagara-on-the-Lake, Ontario

Sept 2027

Georgina Marathon

0 min

Georgina, Ontario

12 Sept 2027Road69m gainFull

12 Sept 2027 Uniformed Services Run Marathon, St. Johns, Ontario
19 Sept 2027 That Dam Hill Marathon, London, Ontario

Oct 2027

Muskoka Marathon

-1 min

Huntsville, Ontario

3 Oct 2027Road183m gainFull

Ottawa Fall Colours Marathon

+3 min

Ottawa, Ontario

10 Oct 2027Road325m gainFull

Toronto Waterfront Marathon

-8 min

Toronto, Ontario

16 Oct 2027Road57m gainFull

Niagara Falls Marathon

-8 min

Niagra Falls, Ontario

24 Oct 2027Road42m gainFull

3 Oct 2027 County Marathon, Picton, Ontario

Nov 2027

Hamilton Marathon Road2Hope

-6 min

Hamilton, Ontario

7 Nov 2027Road81m gainFull

Half marathons in Ontario (5)

Apr 2027

Mississauga Half Marathon

-4 min

Mississauga, Ontario

25 Apr 2027Road45m gainHalf

June 2027

Forest City Road Races Half Marathon

+2 min

London, Ontario

6 June 2027Road134m gainHalf

Aug 2027

22 Aug 2027 GLO Toronto Half Marathon/10K/5K, Toronto, Ontario

Oct 2027

Toronto Waterfront Half Marathon

-3 min

Toronto, Ontario

16 Oct 2027Road61m gainHalf

Niagara Falls Half Marathon

-4 min

Niagara Falls, Ontario

24 Oct 2027Road30m gainHalf

Marathons in Ontario at a glance

Busiest month: Oct 2027, with 7 races.
A typical marathon here climbs about 94m in total (the median of 11 rated courses), against about 142m across Canada.
A typical half marathon here climbs about 61m in total (the median of 4 rated courses), against about 103m across Canada.
Hilliest: Ottawa Fall Colours Marathon, with 325m of climbing (road).
Coolest race day on average: Toronto Marathon (May 2027, a typical high of 12°C). Warmest: Georgina Marathon (Sept 2027, 24°C).

Marathons in other provinces and territories

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