Australia has a pretty strong sports culture and basketball is no exception. People tend to think that women's basketball is popular in Australia, but participation-wise it has historically trailed soccer and netball on the team side, not counting significant participation in individual sports. The advantage that basketball has is that there has been a path to full scholarships at American colleges and better potential for global acclaim and playing professionally around the world. Soccer is competing with basketball for high level professional opportunities now. Netball pays pretty well locally and given that it was created by changing the rules of basketball, there are players who play both competitively. The big threat is that Australian Rules Football has a national women's professional league with teams in the same organizations as men's teams so money is pouring in now. Some percentage of women's basketball players in Australia grew up wanting to play only to pursue basketball because they saw no path beyond local amateur or semipro football and a number of them are switching sports. Some of them are able to play both when the seasons do not overlap and Tessa Lavey took it one step further by playing both at the same time, playing football when there were two games on the same day.
The WNBL is the highest level. Depending on ownership situations at any given time, some teams are owned by the basketball authority of the state that they operate in and government funding is often given as well. A substantial number of players also have jobs or gigs or attend Australian universities along with playing in the league. Besides the paid players, which now has a minimum salary attached, teams are allowed development players who are young and unpaid, which is how the best young players can participate and still maintain NCAA eligibility.
The base to the development system is the local club, which is kind of like how a lot of club sports operate in the United States. Clubs have youth teams and then generally have a senior team without age limits. They also tend to run a lot of local competitions, including rec leagues and they are funded by a mix of player fees and local government grants or business sponsorships. Youth teams compete with each other and players are trying to impress the people who run the state youth teams so they can compete in the national championships for their age. The top young players are given scholarships to the Basketball Australia Centre of Excellence as a part of the Australian Institute of Sport, which is known for elite development in many sports. That is one of the reasons that the NBA chose to open an NBA Academy site there and exchange knowledge on youth development in basketball. AIS used to field a team of their scholarship holders in the WNBL, but their boy's and girl's teams have bounced around since then.
For years, Basketball Australia administered the SEABL, which had the senior teams of top clubs across several states while each state association also ran leagues locally with all of these competitions happening during the WNBL/NBL offseason. After that fell apart, a new league called the NBL1 was formed starting mostly in Victoria and Tasmania. Queensland's league joined as well as South Australia and Western Australia and this season the last division covering New South Wales and the Australian Capital Territory was formed and a team from the Northern Territory joined the Queensland division so besides division play, there will be a national championship at the end of the season. With a few exceptions, clubs have to field both men's and women's teams. There are still plenty of clubs that are not at this level and play in state or regional competitions. Besides foreign players limits of two players, not counting New Zealanders, there are restricted player rules to prevent any one club from fielding too many WNBL/NBL level players. Pay is not that high at this level, but foreign players make extra money working another job or coaching youth for their clubs. For the good WNBL players, the combined income of both leagues can be enough for them to only focus on basketball. A lot of the Australians who pursue better money in Europe play NBL1 in that offseason as well. Otherwise, clubs have most of their bench players barely being paid or field amateurs heading to college in the United States.
Even the clubs at levels below NBL1 are generally interested in signing American players. A decent number of them end up permanently settling in Australia. Men's basketball was especially popular several decades ago and that is why a lot of Australian players with either one or two American parents are well known names in basketball these days.