Wangui was issued with a two year competition ban in 2018 after failing a doping test at the Milano City Marathon at which she had initially been recorded in first place.

John Kanyi, a local runner who was based in Japan, encouraged her to try for an athletic scholarship to enable her to study and train there as well.

[2] While in Japan, she won the 1500 metres at the high school championships and, after graduation in 2002, she commenced training with the Suzuki Track and Field Club.

[10] At the national Olympic trials she won the 10,000 m and came second over 5000 m. Despite her wish to compete in both events, the Kenyan selectors instead chose her just for the 10,000 m, choosing Vivian Cheruiyot for the shorter distance instead.

[2] In her second outing on the Olympic stage at the 2008 Beijing Games she finished seventh in the 10,000 metres, running a personal best time of 30:39.96 minutes.

[12] She then travelled to the Delhi Half Marathon and won in a personal best of 1:07:04 hours ahead of fellow Kenyan Sharon Cherop.

[16] She won the 2013 Ras Al Khaimah Half Marathon with a new personal best of 1:06:09, just 19 seconds off Mary Keitany's world record.

[18] She was selected for the Kenyan marathon team at the 2013 World Championships in Athletics but performed poorly in Moscow, finishing 24th in a time of 2:44:06 hours.