Joseph A. Simoens qualified as a licenciate in both medicine and surgery at Bombay (now Mumbai), India; then as a licentiate of the Royal College of Physicians (LRCP) of England in 1884, and finally as Doctor of Medicine at Bruxelles (Brussels), Belgium, in 1885. That same year he applied for registration as physician, surgeon and accoucheur (male midwife) in the Colony of Natal, and also requested employment there. However, he soon came to the South African Republic (Transvaal), where he was admitted to practice in 1886, and settled in Barberton. There he (identified as Dr S. Simoens by Laidler & Gelfand, 1971) became a member of the hospital committee and with Dr O.F.W. Somershield worked hard to establish the town's first hospital, which was opened in a house later that year. In 1890, while still at Barberton, he published Advice and instructions for the prevention and cure of fever, which is prevalent in the low districts of the Transvaal, in Delagoa Bay, and East Africa (Port Elizabeth, 1890, 24p). The text was in both English and Dutch.
By 1897 Simoens was practising in Komatipoort and at Delagoa Bay (now Maputo, Mozambique) and was a member of the South African Medical Association.