When Diane Donald, now a mom, got a job in journalism after college, she earned less in a year 'than Luke was making in a bad week.' Melanie Burford/Prime for The Wall Street Journal

I have been hanging out with the girls recently, girls being what the PGA Tour wives mostly call each other. Their numbers have dwindled for this week's season-concluding PGA Tour Championship in Atlanta, with its field winnowed to 30 by the previous three FedEx Cup Playoffs events. But at most full-field tournaments the majority of players have their wives or girlfriends in tow, and usually their kids, too, if the kids are young. More than one Tour wife made the analogy to a traveling circus.

"It's like a large family out here, more than anything else," Sybi Kuchar (wife of Matt) told me at the Barclays last month. "Most of it's great, but ask me on Sunday mornings about the glamour."

That's when the wives, assuming their husbands are still in the tournament, usually have to check out of their hotels. With two kids and possibly a nanny, a Tour family might occupy three hotel rooms and travel with a dozen bags, including giant ones for everything from toys to extra golf equipment.

The stereotypical image of pro athletes' wives isn't entirely misplaced on the PGA Tour. If you need help spotting Tour wives as they follow their husbands during tournament rounds, look for two or three women walking together, often in their 20s or 30s with giant sparkling rocks on their left ring fingers. They are, as a rule, uncommonly pretty, but mostly under the radar. The public sees a wife mainly when hubby wins an event and she herds the children, inevitably adorable, onto the 18th green to give him a hug. That doesn't happen after Homer Bailey throws a no-hitter or Kobe Bryant hits one at the buzzer. Golf is a different universe.

Among the few generalizations I can make about Tour wives, based on conversations with about a dozen, is that most make a point of walking the course for some of their husbands' rounds each week.

"It's mild exercise," said Diane Donald. "And it makes Luke feel better."

Back in their younger days—Diane now is 30 and Luke is 35—the two used to flirt more on the course. Now not so much. "We're old and jaded," she joked. But Luke knows she's there and occasionally, even though she isn't much of a golfer, she notices something. Once she was able to point out that Luke's putting routine had become too quick.

"Nothing I do on the course really makes much difference," she said. "But it's good to know what he's going through. If Luke plays bad and comes home upset, the last thing he needs is for me to be upset, too. What he needs to come home to, or to the hotel to, is a calm family atmosphere." Diane and the couple's two daughters accompany Luke to 15 or so events a year.

Like many of the wives I talked to, Diane Donald can't believe she's married to a sports star, much less that she doesn't have a career of her own. She grew up in Chicago, the daughter of a working mother. "I was in day care from 3 months old, that's how much of a career woman my mom was," she said. She got a journalism degree at Northwestern (where she met Luke). After graduating she started in a job that paid $25,000. "That was for an entire year," she said. "That's less than Luke was making in a bad week." Especially once the kids came, it made no sense for her to continue.

Unlike athletes in team sports, pro golfers are independent contractors, so wives are key parts of the family business. A handful are involved directly with the golf side of things. Patrick Reed's wife, Justine, was on the bag last month when he won his first Tour event, at the Wyndham.

Billy Horschel's wife, Brittany, serves as a kind a traveling coach. She played golf at the University of Florida (as did Billy) but had to abandon her own pro dreams after a series of wrist surgeries. She sits in on Billy's lessons with instructor Todd Anderson and helps during tournaments to keep Billy on plan. She has a sports-management degree from Florida.

"All the wives help manage their husbands in one way or another," she told me.

I walked a few holes at the Barclays with Sybi Kuchar and Dowd Simpson (wife of Webb). Good friends, they were thrilled when their husbands were paired together for the first two rounds. Among other topics, they extolled the virtues of Target, which their kids love partly because the stores provide continuity from one town to the next, and of Chipotle restaurants, where Dowd has standing orders she zaps to the nearest franchise from her smartphone for takeout.

The worst things about life on Tour? When kids get sick, Dowd says: "You spend a lot of time in emergency rooms." Sybi voted for guys in the gallery who learn you're a Tour wife and say, "I'll bet you can't wait to spend that check" when Matt is in contention. "What? I mean, it's very offensive. All you can do is laugh and move on," she said.

Amy Mickelson told me the happiest wives on Tour are those with a lot of self confidence. "It's a weird life. You find yourself in a lot of situations where you're just known as the 'wife of.' You have to be able to handle that," she said.

But she said life on the Tour these days is better than it's ever been, thanks to the huge increase in prize money in the Tiger Woods era, which makes it financially feasible for most players to travel with their families. "When Phil and I first came out [in the mid-1990s], only maybe the top 30 or 40 players at most could afford to bring their wives and kids on a regular basis," she said.

The Tour provides free day care, referred to as "school," with the same traveling teachers each week. "My kids probably know the kids out here on Tour better than anyone else," Lori Points (wife of D.A.) said. Many of the wives also bond during outings sponsored by the PGA Tour Wives Association, now in its 25th year. "People might think we're just a club, but our main purpose is to go out into communities and make a difference," said Amy Wilson (wife of Mark), the group's president and a former management consultant with Accenture. In 18 to 20 Tour-stop cities a year, the wives do things like help finish Habitat for Humanity homes and pack backpacks with food and supplies for poor children. To raise money for charity, the group has also published a coffee-table book, "Beyond the Fairways and Greens: A Look Inside the Lives of PGA Tour Families." (And yes, it's not exactly a tell-all.)

Last week at the BMW in Chicago, a dozen wives donned pink aprons to cook a meal for the residents of a Ronald McDonald House. Among them was Diane Donald, who happens to be on regional Ronald McDonald charity board.

"No one wants to meet just us wives, because frankly we're not that interesting," she said. "But we do have some visibility and it would be a shame to let that go to waste."

Write to John Paul Newport at johnpaulnewport@wsj.com

Corrections & Amplifications
The first name of Patrick Reed's wife, Justine, was incorrectly given as Nicki in an earlier version of this article.