Brooke Walker spent that first night watching as much Australian rules football as she could. She did the same the next night, and the night after that. She had a lot of research to do, and not much time to do it. She was going to be paid to play the game at its highest level. It was probably a good idea, she thought, to figure out how it worked.

Walker had not grown up playing what is, depending on whom you ask, Australia’s most popular sport. She was born in New Zealand, unabashed rugby territory. Her first sporting loves had been some of that sport’s many varieties.

As a child, she had played touch, the minimal-contact version, and rugby league. After her family moved to Australia when she was a teenager, she proved good enough at the small-sided version of the sport, rugby sevens, to travel to the 2016 Olympics with her adopted homeland.

Australian rules, by contrast, had never really appeared on Walker’s radar. “Even when I was 14 or 15, I wouldn’t ever have seen it,” she said. “I didn’t even know who played in it.” That held until she was 24, when one of the Australian Football League’s most popular, most powerful teams — Carlton, based in the game’s Melbourne heartland — called and asked if she would like to play in it.

What she was about to learn was that her skills, her age and her gender had arrived at a sporting moment rich in options. With Australian rules, rugby and — with the World Cup looming — soccer eager to expand opportunities for women, and all of them fishing in the same small talent pool, it is suddenly a very good time to be a female athlete in Australia.

Code Switching

The idea that Walker might suddenly take up an elite sport she had barely even watched did not strike her as especially unusual. The rivalries among Australia’s multiple forms of football — Australian rules, rugby union, rugby league and soccer — might be deep-rooted and intense, but the lines between them, for the players, have always been somewhat blurred.

Dozens of athletes have represented the country in both full-size forms of rugby, including some of the most popular figures in the nation’s sporting pantheon. Several have competed in Australia’s two most popular domestic sports leagues, the Australian Football League and the National Rugby League, at various points in their careers.

Walker knew that her experience in rugby sevens made her a candidate to become what is known as a “cross-coder.” “There are a base of fundamentals that transition over,” she said. “The speed, the conditioning, the defensive awareness is all similar.” She knew, too, that the A.F.L. was in desperate need of female prospects. It had a league to build, and she fit the bill.

In 2017, the A.F.L. had launched its first national women’s competition, the A.F.L.W., hoping to capitalize on growing numbers of women and girls playing Australian rules football. The first iteration comprised only eight teams. By 2022, it had expanded to 18, meaning every men’s club now has a women’s division.

Not to be outdone, the N.R.L. followed suit, establishing its first women’s league in 2018. It started with four teams in its first season, a figure that has now grown to 10. (The N.R.L. men’s tournament is contested by 17 teams from across Australia and New Zealand.) The six-team Super W, the rugby union equivalent, started in the same year. Soccer, by these standards, was a trailblazer: The A-League Women has been running since 2008.

Both the A.F.L.W. and the N.R.L.W. are currently semiprofessional, and neither pay nor conditions are optimal. Salaries average around $30,000 in the women’s rugby league, and are a little more for women in the A.F.L. Like all of her teammates, Walker has a full-time job outside her sport, working as a physical education and health teacher in a suburb of Melbourne. She trains in the evening.

That is not the only grievance. Players in both leagues have complained about a shortage of games, a lack of training time, access to training facilities and the scheduling of the season.

There is, though, no shortage of ambition. Andrew Abdo, the chief executive of the N.R.L., has described the growth of the women’s game as a priority for the sport’s governing body, “from grass roots to the elite.” Erin Phillips, one of the A.F.L.W.’s most high-profile stars, has said that the “aim for the players is to be full-time athletes.” Her league has set itself the target of making its players the highest-paid female athletes in Australia by 2030.

Fulfilling those lofty aims has, to some extent, placed the leagues in direct competition. The A.F.L.W., in particular, spread its nets far and wide to entice talent, recruiting athletes with the raw materials to succeed, regardless of background. In the year Walker joined, her fellow new recruits came from sports as diverse as soccer, basketball, netball and tennis.

Walker, then, was in some way an easy study. After the Olympics, she had taken some time away from sports entirely, conscious that she had sacrificed “living my normal life” in order to dedicate herself to rugby sevens. She accepted the offer to play for Carlton, in a sport she “did not understand at all,” because she found the intellectual challenge of learning how to play it “refreshing.”

Even then, the transition was not entirely smooth. Some aspects of the game came easier than others. “The tackle technique in rugby is so precise that in the A.F.L.W. it’s a real advantage,” Walker said. “But game knowledge, strategies, specific skills and techniques — five years on, I’m still learning some of that.”

There were occasional moments, too, when she questioned the wisdom of her choice. “In my first game, my first touch of the ball, I forgot that you had to bounce it after 10 or 15 meters,” she said. “The referee pulled me up and penalized me for holding. At that point, I just thought, What have I done? This is going to be disastrous.”

New Frontier

How the leagues work together may be crucial to their future success. The N.R.L.W., for example, has recruited so heavily from rugby union that at least one coach has voiced his concerns that the two codes will end up “cannibalizing each other.” It would be better, the rugby union coach Campbell Aitken said, if a talent-sharing agreement could be established.

That, certainly, would be Walker’s view. In 2020, intrigued by the idea of playing rugby league again, she registered for an amateur club. She did well enough that she was soon selected to play for her state. That led, in turn, to an offer from the Parramatta Eels of the National Rugby League.

She gave Carlton 12 months’ warning, pointing out that the seasons did not overlap, and duly switched codes once again. “It was my first love of sport, and I wanted to have a go,” she said. “It was another great challenge, understanding the strategies. I had an awesome time.” In the end, she had to miss only a single Carlton game, when Parramatta’s season ran long. “I finished up in rugby, came back, and played for Carlton on the Saturday,” she said.

Walker — since traded to another Australian rules powerhouse, Essendon — has reveled in the precise juncture in Australian women’s sports in which she has spent her career: the blend between the blossoming opportunity of the world that is to come and the freedom of movement that lingers from the one being left behind.

She knows, though, that it will not last. Fully professional leagues will not allow the players to switch codes so easily, and professionalization will most likely keep them from experimenting with so many different disciplines when they are teenagers. Her journey may be much more difficult to replicate in five or 10 years.

Walker is sure, though, that what comes next will be even better. “Imagine a talented teenage girl coming through in a few years’ time, when all of these leagues are professional, who has all of the prerequisites,” she said. “The demand for them will be huge, whether it is to play A.F.L. or N.R.L. or sevens or soccer full-time.”

Walker’s talent gave her the choice. Those who follow her, she believes, will be the ones who finally get the rewards they deserve.