9 Surprisingly Specific Rules Players and Fans Must Follow at the US Open

From what fans can wear and carry to bathroom breaks, selfies and even how quickly players must start a match, the US Open has some surprisingly specific rules.

Ben Shelton of the U.S. in action during his third round match against Canada's Denis Shapovalov. | Brendan Mcdermid-Reuters via Imagn Images

The U.S. Open has a reputation for being tennis at its loudest.

Arthur Ashe Stadium can feel more like an arena than a traditional tennis court, celebrities fill the suites and the grounds have become as much a late-summer New York social scene as a sporting event. Players have embraced that personality, too, arriving in elaborate walk-on looks and feeding off crowds that rarely behave like the ones at Wimbledon.

But freewheeling does not mean anything goes.

Behind the spectacle is a surprisingly detailed collection of rules governing everyone from the stars on court to the fans taking selfies in the stands. Some are practical. Others are oddly specific. A few might make even regular US Open attendees check the fine print.

Here are nine worth knowing.

1. There Is a US Open Dress Code, Just Not the One You Might Expect

Forget Wimbledon's famous whites. The US Open gives players considerably more freedom with color and personal style, which has helped turn the tournament into tennis's unofficial fashion week.

Naomi Osaka’s Allen Iverson inspired look for the 2026 US Open has so many details.

Whether you love it or hate it, no one is doing fashion in tennis like her.
pic.twitter.com/50PUF7F30X

— The Tennis Letter (@TheTennisLetter) September 1, 2026

There are still boundaries. Players are expected to wear professional tennis attire, while the USTA can regulate elements such as branding and logo size.

Fans get more freedom. The US Open says there is no formal spectator dress code, and even encourages guests to dress up if they want. There is one baseline requirement: shirts and footwear must stay on. Clothing or accessories carrying offensive or inappropriate imagery can also be prohibited.

2. Your US Open Outfit Can Be Fine, but Your Backpack Is Not

Planning the perfect US Open look? Plan the bag with equal care.

Backpacks are prohibited, with limited exceptions including single-compartment drawstring bags and certain medical needs. Guests are allowed only one bag, and it cannot exceed 12 by 12 by 16 inches.

That designer tote may pass. Your everyday backpack probably will not.

3. There Are Rules for Taking That Courtside Selfie

A seat inside Arthur Ashe Stadium naturally invites a photo. Just watch when you take it.

The tournament specifically asks fans to avoid flash photography and light rings during match play. The US Open recommends using changeovers and breaks between sets for photos instead.

In other words, getting the shot is fine. Distracting a player while doing it is not.

4. Players Are Literally on the Clock Before the Match Starts

Even the pre-match routine comes with a countdown.

The US Open uses what is commonly called the "1-4-1" procedure. Players have one minute after reaching the court to meet the chair umpire for the coin toss, followed by a four-minute warmup and another minute to prepare for the opening point.

Once play begins, players generally have 25 seconds between points.

5. Bathroom Breaks Are Regulated

Even a trip to the bathroom comes with rules at a Grand Slam.

Players cannot simply disappear from the court whenever they want. Toilet and change-of-attire breaks are governed by Grand Slam rules, with the number available depending on the match format.

The regulations go further than simply counting breaks. An official can accompany a player leaving the court to ensure the break is being used for its authorized purpose.

Tennis really does have a rule for nearly everything.

6. Fans Can't Pop Open an Umbrella During Play

An umbrella makes perfect sense during a long day outdoors in New York. Just don't open it at the wrong moment.

The US Open's guest code specifically prohibits spectators from using an umbrella in the open position during play.

Considering the sight lines inside a tennis stadium, anyone sitting behind you will probably appreciate this one.

7. Moving Around During a Point Can Be a Problem

This is one of the biggest adjustments for fans accustomed to football, basketball or baseball.

The US Open asks spectators not to leave their seats while a player is serving when they are within the player's view. Fans are also expected to keep their voices down during serves and points before letting loose once the point ends.

That contrast is part of what makes New York unusual: deafening celebration one moment, near-silence the next.

8. You Can Bring a Water Bottle, but Not Just Any Water Bottle

The US Open has a surprisingly specific hydration rule.

Glass bottles, containers and cans are prohibited, but fans may bring a reusable metal or plastic water bottle measuring 24 ounces or less. Refill stations are located around the grounds.

One other packing note: sealed packages are on the prohibited-items list, too.

9. Even Celebrating Has Its Limits

New York crowds are famously loud, and the US Open hardly discourages enthusiasm. But there is a line.

Guests cannot use whistles or make other sounds that could confuse players, and disruptive or offensive behavior can lead to ejection. Fans also cannot throw objects onto the court, enter restricted player areas or interfere with play.

That balancing act is part of the US Open's identity. It wants the noise, fashion, celebrity sightings and distinctly New York energy that separate it from the sport's more traditional stops. It just wants all of that to stop short of affecting the tennis.

And at a tournament where even the size of your water bottle is regulated, it pays to know exactly where that line is.