Inside the InterContinental Los Angeles Downtown, a towering luxury hotel with a rooftop pool and soaring views of the city, Jason Hernandez said on Monday that things seemed normal. Housekeepers had cleaned his room. The lobby was tidy, if a little quiet.

It wasn’t until he stepped outside and encountered metal security barricades in front of the hotel’s doors and scores of people marching, chanting and banging drums that it was clear his vacation plans had collided with a major strike by thousands of hotel workers.

Roughly 15,000 housekeepers, cooks and front desk clerks across the region walked off the job over the weekend, demanding higher pay and better benefits. The strike, which started on Sunday, has coincided with a long July Fourth holiday weekend as thousands of visitors arrived for conventions, weddings and parties.

“Inside, you kind of forget,” said Mr. Hernandez, 26, who was in town for Anime Expo, a celebration of Japanese animation, and dressed as a League of Legends character in a long brown loin cloth with a teal jewel on his forehead. “Then it’s like, ‘Oh my gosh, all this crazy stuff’s happening.”

Although Mr. Hernandez and his friends had decided to splurge on a hotel room for the expo, which drew tens of thousands of fans to downtown Los Angeles, he said he wasn’t bothered by the commotion.

“I’m for the cause, so I don’t mind it at all,” said Mr. Hernandez, a public-school teacher from Orange County, south of Los Angeles. “It’s hard to live, just in general. Everything’s going up.”

That’s a view that leaders of the union representing the workers, Unite Here Local 11, believe is reverberating widely — even among hotel guests and vacationers — in a region where workers say pay hasn’t kept pace with rents or the price of gas and groceries.

“The support in the community is overwhelming,” said Kurt Petersen, a co-president of the union. “Workers who are paid a living wage will make this city better.”

Outside several large downtown hotels on Monday morning, crowds of workers in red T-shirts that read “En Huelga,” or “On Strike,” intermingled with clusters of convention attendees wearing a variety of colorful wigs, tiny dresses or wizard robes.

Oscar Orellana, 30, paused in the shade of the InterContinental and waved back at one of the drivers who honked while passing by.

For six years, Mr. Orellana has worked in the housekeeping department at the hotel, where he ensures that linens are stocked on each floor. His parents, too, long worked in hotel housekeeping; his father was picketing at a nearby Ritz-Carlton, he said.

“I used to see my parents, and they loved their job, which made me want to go into the hotel world, and I love my job,” he said. But his three-hour round-trip commute from Long Beach, about 25 miles away, along with his heavier workload and the inability to comfortably afford an occasional sweet treat for his 4-year-old, has made it “impossible for us to be in there working — that’s why we’re out here striking,” he said.

To the west, at the upscale Fairmont Miramar Hotel & Bungalows in Santa Monica, dozens of workers picketed outside the manicured flowering hedges lining the property. A few guests said the hotel seemed to be running well overall, but they were frustrated by small inconveniences — like a shortage of clean towels — at such a pricey property. They also felt caught in an awkward social position during a time when they just wanted to relax.

“I’m a union worker, so I can sympathize if they’re not getting paid fair wages,” said John Smith, 38, who was visiting with his wife from San Bernardino.

But, he added, “we’re trying to enjoy the holiday — I took two days off for this.”

Just outside the property, on a street corner, a bride and groom posed for photos with their arms around each other. Yards away from them, striking workers wearing bright red could be seen marching and waving signs above their heads.

The hotel’s management did not immediately respond to a request for comment.

Most of the hotels have contingency staffing plans and expect to be able to serve guests largely without interruption, said Pete Hillan, a spokesman for the Hotel Association of Los Angeles. Large hotel chains, for instance, have brought in employees from other properties unaffected by the strike or have asked managers to step in, he added.

In the longer term, a high-profile walkout on a major holiday weekend could diminish Los Angeles’s reputation as a destination for convention planners, business travelers and tourists, he said.

“Why would they come to L.A.?” he asked. “People vote with their feet.”

The hotel workers’ strike is just the latest high-profile union action amid what California leaders have taken to calling a “hot labor summer,” as struggles to afford sky-high costs of living have bred unusual levels of solidarity among workers in disparate industries, from public school aides to dockworkers to Hollywood screenwriters.

Teamsters and nurses have shown up to picket lines outside Hollywood studios, where screenwriters have been on strike since May. This week, leaders of the Writers Guild of America, the union representing screenwriters, joined hotel workers in their protest.

Elected officials in Los Angeles — a Democratic stronghold where labor unions have, over decades, amassed significant political might — have also been eager to show their support for the striking workers.

Representative Adam Schiff, Democrat of California, picketed on Sunday alongside workers at a hotel near Universal Studios Hollywood.

“They ought to be able to earn a decent living, decent wages,” Mr. Schiff told reporters. “I’m proud to be here and stand shoulder to shoulder with my brothers and sisters in labor.”

The union has asked that hourly wages, now $20 and $25 for housekeepers, immediately rise by $5, followed by a $3 increase in each subsequent year of a three-year contract.

Hotel industry officials have said that many of the union’s other demands — including an additional charge for guests at unionized hotels that would go toward a worker housing fund — were attempts to saddle hotel operators with the costs of the region’s housing crisis.

Keith Grossman, a spokesman for a group of more than 40 hotels in Los Angeles and Orange Counties that are bargaining with the union, said, “Based on the union’s actions, it’s clear the union is not focused on the interests of our employees and its members and is instead focused on its political agenda.”

Mr. Grossman said that the hotels had offered to increase pay for housekeepers making $25 an hour in Beverly Hills and downtown Los Angeles to more than $31 per hour by January 2027.

As the country heads into a hectic summer travel season, union leaders have declined to speculate on whether the strike will last for days, weeks or months. But they said that workers would continue protesting until contract deals were reached.

Kurtis Lee contributed reporting.