WXV Starts This Weekend With a New Size 4.5 Rugby Ball — Here’s What It Means
By The Rugby Fan Central Team
The new WXV Global Series begins this weekend, but when some of the world’s best women’s rugby players take the field, they will be playing with something different.
The ball.
Beginning Saturday, September 12, World Rugby will extend its trial of a women’s-specific size 4.5 rugby ball into elite international 15s during the 2026 WXV Global Series.
The experimental ball has smaller dimensions than the traditional size 5 but retains the same weight, according to World Rugby.
It may sound like a small change.
At international level, however, changing the dimensions of the ball could affect passing, catching, kicking, offloading and lineout throwing.
That is exactly what World Rugby wants to study.
New to the experiment? RFC’s Size 4.5 Rugby Ball explainer breaks down how the ball differs from a traditional size 5, why World Rugby is testing it and what could happen next.
And with the USA Women’s Eagles among the 12 teams competing in the main WXV Global Series, American players will be part of the experiment.
The Size 4.5 Ball Trial
WXV Begins September 12
The 2026 competition marks the beginning of a completely revamped WXV.
Instead of the previous centralized WXV 1, WXV 2 and WXV 3 format, the top 12 nations will compete through a home-and-away, cross-regional touring model.
Australia, Canada, England, France, Ireland, Italy, Japan, New Zealand, Scotland, South Africa, USA and Wales make up the main Global Series.
The eight-week international window runs from September 12 through October 31, with 36 matches scheduled.
England hosts Australia on opening weekend, Scotland faces Canada in Edinburgh and France meets New Zealand in Lyon.
Alongside the new competition format comes another significant experiment.
The size 4.5 ball trial is moving into elite international 15s.
For a deeper look at how the new WXV format works, see RFC’s guide to the new WXV Global Series and Challenger structure.
What Is the Size 4.5 Ball?
Senior women’s rugby has traditionally used the same standard size 5 ball used in the senior men’s game.
The experimental ball changes that.
World Rugby describes it as a women’s-specific size 4.5 ball, developed in partnership with Gilbert.
It uses bespoke dimensions but maintains the same weight and advanced aerodynamic and technological features as a standard size 5.
That distinction matters.
This is not simply a lighter rugby ball or a junior ball being introduced into international rugby.
It is equipment specifically developed for the women’s game and now being tested at the highest level.
Rugby Fan Central contacted Gilbert for additional comment on the Size 4.5 ball and its use during the WXV trial but had not received a response at the time of publication.
Why Is World Rugby Testing It?
The question behind the trial is straightforward:
Could a ball designed specifically for female players provide a better platform for skill execution?
Handling touches almost every part of attacking rugby.
Players must control the ball while passing, catching, carrying, offloading and operating under defensive pressure.
A slightly smaller ball could potentially make certain skills easier to execute.
But World Rugby has not declared that the size 4.5 ball is better.
That is why this remains a trial.
World Rugby says it will examine player feedback, injury surveillance and shape-of-the-game data before determining what should happen next.
This Experiment Didn’t Start With WXV
WXV is a major step because the trial is moving into elite international 15-a-side rugby.
But it did not begin here.
The women’s-specific ball has already been tested in other environments, and World Rugby expanded the trial into elite international sevens with the 2026 HSBC SVNS Series.
World Rugby says anecdotal feedback from the sevens trial has been positive.
The governing body has also continued to evolve the ball based on player feedback.
Now comes a very different test.
Fifteens brings more structured set-piece play and different tactical demands than sevens.
The size 4.5 ball will be tested through long tactical kicks, goal attempts, lineout throws, multi-phase attacks and sustained periods of territorial rugby.
That should give World Rugby another layer of evidence about how the ball affects elite competition.
Why WXV Could Tell Us Much More
A ball that works well in sevens does not automatically produce the same results in 15s.
The two formats place different demands on players.
WXV will expose the ball to repeated lineouts, longer kicking exchanges, goal-kicking, more structured possession and longer sequences of phase play.
That makes this international window particularly valuable.
Instead of asking only whether players prefer the feel of the ball, World Rugby can examine whether changing the dimensions actually changes the way elite women’s rugby is played.
How Could the Size 4.5 Ball Change the Game?
Passing & Offloading
Does the smaller ball make one-handed control easier and encourage players to keep the ball alive through contact?
Kicking
Watch goal-kicking accuracy, distance and tactical kicking as players adjust to different ball dimensions.
Lineouts
Hookers may need to adjust highly practiced grip, hand position and release mechanics.
Handling Errors
Does easier control translate into fewer knock-ons and handling mistakes across the WXV window?
Why Not Just Keep the Size 5 Ball?
That is one of the central questions surrounding the trial.
Elite women’s rugby has already reached an extremely high technical standard using a size 5 ball.
Players have spent years — often decades — developing their passing, kicking and throwing techniques around it.
So there is a legitimate question:
What problem is the smaller ball trying to solve?
Supporters of the trial can argue that equipment does not need to be failing before researchers investigate whether it can be improved.
If equipment developed specifically for female players produces measurable improvements without introducing significant disadvantages, there could be a case for change.
Critics can argue that women’s rugby already demonstrates an extremely high level of skill with the traditional ball and that changing such a fundamental piece of equipment should require compelling evidence.
WXV should provide more of that evidence.
The USA Women’s Eagles Are Part of the Experiment
There is also a direct American angle.
The USA Women’s Eagles are one of the 12 teams competing in the main WXV Global Series.
The Eagles recently named a 36-player squad for WXV, bringing together returning internationals, sevens talent and players emerging through the American pathway.
Those players will now be among the athletes providing match data and feedback from the size 4.5 trial.
The experiment will also reach American soil.
World Rugby’s WXV schedule includes USA against Italy in Nashville, giving American rugby fans an opportunity to see the size 4.5 ball being used in elite international 15s.
For U.S. rugby, the implications could eventually extend beyond the Women’s Eagles.
If World Rugby ultimately finds enough evidence to support wider adoption of a women’s-specific ball, questions would naturally follow about its potential use elsewhere in the women’s game.
Follow RFC’s USA Women’s Eagles hub for fixtures, results, players and coverage throughout the international season.
Is Size 4.5 Now the Official Women’s Rugby Ball?
That could mean broader adoption.
It could mean further testing.
The ball could continue to evolve.
Or World Rugby could determine that the evidence does not support making a permanent change.
For now, there is no final decision.
What RFC Will Be Watching This Weekend
The debate now moves onto the field.
Once WXV begins Saturday, the most interesting question will not simply be whether players say they like or dislike the ball.
It will be whether we can see a difference.
Are players more comfortable offloading?
Do handling errors change?
Do hookers experience problems adjusting at the lineout?
Does the ball affect tactical or goal kicking?
And ultimately, does women’s international rugby look meaningfully different with a size 4.5 ball?
One weekend will not answer all of those questions.
But across 36 WXV Global Series matches, World Rugby should begin accumulating considerably more evidence.
The Bottom Line
The new WXV Global Series begins this weekend with a new competition format — and a significant equipment experiment.
For the first time, World Rugby’s women’s-specific size 4.5 ball trial is moving into elite international 15-a-side rugby.
The ball has smaller bespoke dimensions but the same weight as the traditional size 5.
World Rugby says earlier feedback has been positive.
But the governing body has not decided that the size 4.5 ball should permanently replace the size 5.
WXV is designed to help answer that question.
Beginning Saturday, some of the best women’s rugby players in the world will provide the biggest test yet.
Follow WXV 2026
WXV is back with a new global format, a new international window and plenty to follow for the USA Women’s Eagles. Continue with RFC’s latest guides, squad coverage and analysis.
How Does the New WXV Global Series Work?
Understand the new Global Series, Challenger competition and how women’s international rugby fits together in 2026.
READ THE WXV GUIDE →USA WOMEN’S EAGLESMeet the USA Squad for WXV 2026
See the Women’s Eagles squad selected for the 2026 WXV Global Series and the international window ahead.
VIEW THE USA SQUAD →TEAM HUBUSA Women’s Eagles Hub
Follow USA fixtures, results, players and RFC coverage throughout WXV and the international season.
FOLLOW THE EAGLES →RFC EXPLAINSWhy Is Women’s Rugby Trialing a Size 4.5 Ball?
Go deeper on the new ball, how it differs from a Size 5 and why World Rugby is testing it.
READ THE EXPLAINER →