The 23-year-old, who has moved from Cardiff City, has 24 caps as a international footballer.
She was in the Wales netball team at the Glasgow Commonwealth Games in 2014, but recently admitted that trying to play both sports had caused issues.
"There has been some turbulence," she said in a statement on Twitter.
Jones, who played in defence for netball Superleague side Celtic Dragons, highlighted that a clash between domestic netball training and an international football fixture in April had resulted in her being left out of the initial World Cup squad.
She later turned down the chance to return to the squad following the Europe Open Championships in May.
In her statement, Jones continued: "At that point I don't believe the terms put forward were appropriate, and the relationship in place would not have been of benefit to a team going forward to a major championship.
"Many congratulations to the 12 who have made the World Cup squad. I wish the girls all the best for Sydney and look forward to tracking their progress on the world stage."
Reading are currently top of WSL 2, the second-tier of the English game.
Wales dual sport international Nia Jones has joined Women's Super League 2 side Reading after being overlooked for next month's Netball World Cup.