Boston Marathon 2012 Sold Out.

Boston Marathon 2012 is sold out as of 9/23/11. [Charity entries may be available]

Update: 20,000+ entries accepted into Boston Marathon 2012, 3000+ entries rejected.

Around 24,000 finished the race in 2011, and estimates suggest about 25,000 to 26,000 will race in 2012.

The BAA's new 'performance-based' registration process accepted applications from runners who met the qualifying time criteria between 9/12/11 and 9/23/11.

However, BAA notes that many who registered may not be guaranteed entry. Posted on baa.org, 'Entry is not on a first-come, first-served basis . . .'

Applicants will be notified of acceptance or rejection 'next week.'

The 'performance-based' criteria are not clearly defined publicly. Our assumption is that applicants be accepted in order of fastest qualifying time in their age group. If so, will baa.org factor in the degree of difficulty by marathon?

Average finish times can vary among most marathons by 30 minutes or more.  At the extremes: consider a 5:16 average finish time in the Los Angeles Marathon compared to a 3:47 time at the Hamilton Marathon.

See details in our analysis of Top 25 Toughest Marathons.

For everything else, see our Complete Boston Marathon Coverage.

Ironman DNF (Did Not Finish) Rates for 2011 Season

Ask any triathlete which races they think will have the highest rate of starters who did not finish (DNF) for one reason or another, and they'll likely mention one or more of our top 25 Toughest Ironman races. Ironman events in St. George, France, and Lanzarote, featuring monster bike courses, would have been our picks. But the data tells a different story.

Believe it or not, Ironman Lanzarote has the lowest DNF rate: an astonishingly low 2%. St. George easily had the highest DNF rate at 16.5%. France, Regensburg and the new race in Wales all had DNF rates over 10%. The flat courses in Florida and Arizona help limit DNFs, while tough bike courses in Texas and Wisconsin push DNFs to the 7%-8% range.

We took a closer look at Lanzarote and Lake Placid. Lanzarote sorts results by men and women; only 2 women out of 113 starters DNF, 1.8%. Of the men, only 2.1% DNFd. One thing appears to be certain: those who have chosen to race Lanzarote are extremely ready for every challenge on the course. They finish, no matter what. Impressive.

At Ironman Lake Placid 2011, water temperatures were high enough that only those who swam without a wetsuit were eligible to qualify for Kona. More than 600 chose to swim sans wetsuit, and more than 1800 raced with the benefit of wetsuit buoyancy. Was there a difference in DNFs between the wetsuiters and the non-wetsuiters? No. 

Ironman Wales Results Analysis: Compared to Ironman UK

Congratulations to the 1134 triathletes who completed the inaugural Ironman Wales triathlon in an average time of 13:02. Any race over the 13 hour mark is one of the toughest in the world, and the 12% DNF rate, also one of the highest of all ironman events, proves the point.

With two races in the United Kingdom, each known for difficulty (UK average finish time in 2010 was 13:01, nearly identical to 2011 Wales, though in 2011 UK was much faster at 12:35), we compared the two by age group to see how comparable the courses may be.