Mark Goodson and Eddy Lowe, founder members of the British Biathlon Union (BBU) more than 20 years ago, are both stepping down.
Goodson is due to leave his position as secretary general and finance director at the end of this month.
Lowe, meanwhile, is to give up his role as sport and technical director.
Both were instrumental in helping establish the BBU in 1996 as the governing body for the sport in Britain.
Before that, however, Goodson had been chairman of Army Nordic for four years.
Lowe had managed the British biathlon Olympic team at Albertville 1992 and Lillehammer 1994.
Also stepping down from the BBU Board after five years is Colonel Adrian Thurgood.
Thurgood, the former Deputy Commander British Forces Afghanistan, had acted as the BBU director of military liasion and British Championships.
Nearly all biathletes in Britain are serving members of the armed forces.
The British National Championships take place in Ruhpolding in Germany in January, where most of the national squad also train.
The BBU link with the military has been maintained with the appointment of Brigadier John Mead, a member of the Royal Artillery, to the Board.
At the last Winter Olympics in Sochi 2014, Britain were represented by two biathletes.
Lee-Steve Jackson finished 42nd and 67th in the men's individual and sprint.
Amanda Lightfoot came 71st and 75th respectively in the women's individual and sprint.
Lightfoot is set to compete again at Pyeongchang 2018 after finishing 32nd in the individual race at this year's International Biathlon Union World Championships in Hochfilzen but Britain's top male biathlete, Scott Dixon, still has to qualify.