NBL1 South is a semi-professional basketball league in Victoria and Tasmania, Australia, comprising both a men's and women's competition.

NBL1 South was the lone conference in 2019, with North, Central, West and East joining over the proceeding three years.

All Victorian-based SEABL teams joined the new league, while Eltham Wildcats, Knox Raiders, Ringwood Hawks and Waverley Falcons also joined the league from the Big V.[1] The North-West Tasmania Thunder men and Launceston Tornadoes women also kept their place, as did Basketball Australia's Centre of Excellence teams.

With a combined 154 men's and women's games that could not be completed, it was decided to abandon the season with no champions and no individual awards.

[8] * Clubs that transferred from the South East Australian Basketball League (SEABL).