Mara Yamauchi is a top British marathon runner based in Tokyo. In 2006 she became the 2nd fastest British female marathon runner ever when she clocked 2:25:13 to finish 6th in the Flora London marathon. In September 2007 she finished 9th in the World Athletics Championships marathon in Osaka. Her current major goal is to win a medal at the 2008 Beijing Olympics.

Prior to becoming a full-time athlete, Mara worked for the British Foreign & Commonwealth Office. Her first overseas posting as a diplomat was to Tokyo from 1998 to 2002. Before joining the FCO she studied Political Science at Oxford University and the London School of Economics. It was during her student days that Mara started running competitively.

Upon returning to the UK in 2002 after her posting to Japan, Mara resumed her running career seriously. Initially she combined work and training, but in January 2006 she took unpaid leave from the FCO to focus on running 100%, and moved back to Tokyo.

In 2006 Mara won the bronze medal in the Commonwealth Games 10,000m, and is currently ranked 9th in the world road running rankings. She lives and trains in Tokyo with her Japanese husband, Shigetoshi, who also acts as her coach and manager. She is a member of the new Japanese running club, Second Wind AC, and of Harrow AC in the UK. Combining work and running has led to her becoming known in Japan as the "running diplomat".