Shoman was called to the bar in October 1988, and appointed Crown Counsel in the Office of the Director of Public Prosecutions (July 1988), serving for over a year before entering private practice. She was elected the first female president of the Bar Association of Belize in 1996. While in her mid-30s, Shoman was appointed to chair the board of directors of Belize Telecommunications Limited (1998–2000). In December 2009, she was elevated to the rank of Senior Counsel by the then Chief Justice of Belize, Dr Abdulai Conteh.
Her first national appointment came in 2000 when she became Ambassador/Permanent Representative of Belize to the Organization of American States on August 25, 2000, and she served concurrently as High Commissioner of Belize to Canada until 2003. She was also appointed Belize’s ambassador to the United States in August 2000. During her tenure, Shoman served as vice-chair of the Permanent Council of the OAS.
In June 2007, then Prime Minister Said Musa appointed her to the Senate of Belize, and made her the country’s first female Minister of Foreign Affairs & Foreign Trade. Shoman held this position until Musa’s party, the People's United Party, ceded power in 2008, when she returned to private practice.
Shoman has remained an active advocate, heading the legal team challenging controversial constitutional changes proposed by the ruling United Democratic Party. When Prime Minister Dean Barrow alleged that his predecessor, Said Musa had secretly diverted public funds and charged him with theft, Shoman was on the legal team that ensured Musa’s acquittal.
The then Leader of the Opposition, Johnny Briceño appointed Shoman as a Senator for a second time in 2009.