Non-binary runners have had to register for the men's or women's divisions prior to the change.

The new policy was announced along with with the opening of registration for the 2023 race, which is set for April 17.

"While we do not currently have qualifying standards for non-binary athletes, we are working on ways non-binary participants are accepted into the event," the BAA said in a statement.

Those who have completed a marathon as a non-binary participant between September 1 2021 and September 16 2022 can submit an entry for the 2023 Boston Marathon, with entry into the event being determined by an athlete's submitted time and based on the allocated field size.

The registration deadline is September 16.

The BAA said qualifying times have not been established and will be updated in future when more data is collected. 

For now, athletes must make their respective men's and women's division qualifying times, aligning with their sex at birth.

Approximately 30,000 people are expected to compete at the race next year.

Russian and Belarusian residents will not be among them, however, with people who live in the two countries banned because of the war in Ukraine.

They were also banned in 2022.

Russian and Belarusian citizens who are not current residents of either country may compete, but not under a Russian or Belarusian flag.

Non-binary middle-distance runner Nikki Hiltz - who finished second in Sunday's (September 11) 5th Avenue Mile women's race behind new course record-holder Laura Muir, praised the decision to add a non-binary division.

"There's still so much work to be done but I'm thrilled that non-binary runners are being acknowledged by the Boston Marathon and BAA," said Hiltz on Twitter.

Last year, the Philadelphia Distance Run became the first large American race to accommodate non-binary runners in its registration process and this was followed by the Brooklyn Marathon and Half Marathon in April this year.