She participated in Women's freestyle 63 kg at 2008 Summer Olympics losing to Elina Vaseva.

Maria Dunn has won ten Oceania Championships in women's freestyle wrestling.

[6] Dunn was the first-ever Guamanian female wrestler to participate in the Olympic Games, via invitational slot or 'wild card'.

While training in England, Maria met her future husband, English wrestler Nathan Tully.

She did not lose a single match between the 2002 and 2011 Oceania Championships, and decided to move up a weight class to have more competition.

[19] She also won the 2012 Oceania Wrestling Championships, moving back to the 63 kg weight class.