Critics objected to the bidding process, and human rights groups raised concerns about workplace safety for the migrants who will build the stadiums needed to host the event.

Under its de facto leader, Crown Prince Mohammed bin Salman, Saudi Arabia has unleashed a spending spree on global sports, turning the kingdom into a contender for the biggest events.

On Wednesday, soccer’s governing body delivered Saudi Arabia the biggest prize of all: the men’s World Cup in 2034.

No other competition on the planet attracts as many eyeballs as the century-old quadrennial, a national team competition that thrusts host nations into center stage in a way only the Summer Olympics can match.

But human rights groups objected to the Saudi bid, saying the country’s human rights record raises risks for the thousands of migrant workers from some of the poorest parts of the earth who will likely be brought in to build the infrastructure — stadiums, airports, roads and hotels, and even a new city — to stage the tournament.

Other critics, including fan groups, said FIFA — the soccer global body that almost collapsed a decade ago after many of its top leaders were indicted on corruption charges by the U.S. Department of Justice — had rigged the vote for the Saudis by changing the rules for bidding.

Under FIFA’s rules, the organization’s 211 member nations are supposed to select one tournament host during a single vote, and usually there are multiple contenders. This year, though, FIFA’s members picked hosts at the same time for two tournaments: the World Cup in 2030 and 2034. And they were asked to make their selection in a package deal, essentially approving the bids for both tournaments, or for neither.

The only contender for the 2030 event was, for the first time, a group of six countries from three continents — Spain, Portugal, Morocco, Argentina, Uruguay and Paraguay. So any nation that voted against the Saudi bid would also be voting against those countries hosting the 2030 event, too.

The members were told to make their selection by acclamation and without debate. The selections of the two multibillion-dollar tournaments were confirmed after members were asked to raise their hands and applaud during a meeting held on the videoconferencing platform Zoom.

FIFA said recently that the rule changes “followed a comprehensive consultation process across all confederations,” but has not explained why the bids for the two tournaments were combined. Last week, FIFA published an evaluation of the Saudi bid, saying the country was on the path toward reforming its labor system, with changes that will reduce risk to workers engaged in the building work required for the World Cup. Amnesty International denounced that report as an attempt to “whitewash” Saudi Arabia’s “appalling” human rights record.

The announcement of the winning bid was without the fanfare that came when previous candidates secured the event. There were few if any news media from the 2030 host countries present at FIFA’s headquarters and a smattering of Saudi journalists, who cheered when Saudi Arabia’s name was pulled from an envelope.

No one from the winning bid was present at the announcement. Days before the vote, officials in Saudi Arabia distributed a 26-page guide on where to watch nationwide celebrations. A solitary protester, who had traveled from Sweden, stood outside the gates of FIFA’s glass and steel headquarters.

Hosting the World Cup is part of an ambitious plan by Prince Mohammed to reorient his country, in part by diversifying its economy. Sports and entertainment have been at the center of this plan over the past decade as the crown prince brought the world’s top sports and sporting talent to Saudi Arabia, at eye-popping cost.

Within minutes of FIFA’s announcement, Prince Mohammed said his country was determined to spread “messages of love, peace and tolerance” throughout the tournament.

Regional leaders quickly sent celebratory messages, including the ruler of Dubai, Mohammed bin Rashid Al Maktoum, who congratulated the “the brotherly Saudi people for their great ambition and strong will that knows no impossible.”

The Saudis had long said they wanted to use sports as a driver of tourism as part of the project to open up the country.

In the buildup to the decision, the sport minister, Prince Abdulaziz bin Turki Al Faisal, dismissed as “shallow” claims made by advocacy groups that Saudi Arabia’s sudden and enormous focus on sports was a way to distract the world from its human rights record. Similar accusations — known as sportswashing — were made against Saudi Arabia’s neighbor Qatar, which was host to the 2022 World Cup.

Human rights groups point to a recent report commissioned by FIFA about the treatment of migrant workers who built stadiums and other sites in Qatar for that event. Many of those workers were injured and even killed because of the dangerous working conditions.

The report, which took FIFA a year to publish, said the sports body should compensate those hurt and the families of workers killed, as well as workers who were victims of wage theft and unscrupulous middle men involved in the recruitment process.

Michael Page, deputy director of Human Rights Watch’s Middle East division, said the scale of risk posed by Saudi Arabia hosting the tournament was even higher. “There are about 13.4 million migrant workers in Saudi Arabia, compared to two million in Qatar,” Mr. Page said on a call with journalists, in which he was joined by other opponents of the award.

“Many work in remote, harsh conditions that could exacerbate the human cost of hosting the tournament,” he said.

In recent years, tennis, golf, Formula One racing and top level boxing have all been recipients of Saudi munificence, as have some of the highest-profile soccer players in the world, among them Cristiano Ronaldo, who have been lured away from Europe to play in Saudi Arabia.

But getting to host the World Cup is an achievement of another magnitude.

It would be “important on all fronts, particularly reputational risk management,” said Andreas Krieg, a fellow at the Institute of Middle Eastern Studies at King’s College, London, before the announcement was made.

He said winning the bid would allow Saudi Arabia to “complete this whole episode of normalization the kingdom has gone through” after the 2018 murder of the journalist Jamal Khashoggi, an insider-turned-critic of the Saudi monarchy. Mr. Khashoggi was killed inside the Saudi Consulate in Istanbul. An intelligence report published by the Biden administration said Prince Mohammed had approved the killing. The kingdom has denied the allegations.

“It allows the Saudis to say: ‘We are a normal country, and the world is treating us like a normal country,’” he added.

One of the crown prince’s earliest moments in the global spotlight came at the opening game of the 2018 World Cup in Moscow, when he sat alongside FIFA’s president, Gianni Infantino, and President Vladimir V. Putin of Russia as their nations met in the opening game. Since then, the relationship between Saudi Arabia and FIFA, and in particular Mr. Infantino, has deepened, with the FIFA president a frequent visitor to the country.

Last October, FIFA announced that the hosts for the 2034 World Cup would be chosen at the same time as the host for the 2030 event. It said only countries from Asia and Oceania, where New Zealand is the largest country, could bid for the 2034 event because of a rule on continental rotation. Interested countries, FIFA said, would have just a few weeks to formalize their interest.

The move seemed to catch many nations by surprise. Saudi Arabia, however, was ready and within minutes of the FIFA announcement, it said it would bid. Moments later, the regional body for soccer in Asia, run by a member of Bahrain’s ruling family, issued a statement saying the Saudis had the support of the entire region.

That’s because even before it made its bid official, Saudi Arabia had been winning support, signing cooperation agreements and sponsorship agreements with national soccer federations around the world. By the time of the meeting on Wednesday, Saudi Arabia had received 140 official letters of support from among the world’s 211 soccer federations.

“The bidding process has basically been a stitch-up from start to finish,” said Steve Cockburn, Amnesty International’s head of labor rights and sport, calling it “a sham,” before the announcement was official.

He added that the lack of competition weakened the need for Saudi Arabia to improve its human rights record.

The Norwegian federation was the only member to voice opposition to FIFA’s process in selecting the 2030 and 2034 hosts, saying it wanted its objection to be officially recorded. Others either gave their full-throated backing or, like the Swiss and Germans, cautious approval based on Saudi commitments to change.

For FIFA, Saudi Arabia offers two things it requires most: A country willing to spend vast sums of its own money to stage the World Cup and organizers who are likely to face little internal opposition, dissent or discussion that could derail staging plans.

That usually quiet perspective was said out loud by FIFA’s former secretary general, its most senior administrator, as frustrations grew during Brazil’s bumpy road to staging the tournament in 2014. “I will say something which is crazy, but less democracy is sometimes better for organizing a World Cup,” the official, Jerome Valcke, said at the time.

The bid evaluation report for Saudi Arabia that was released by FIFA last week suggested as much.

“Critically, the demonstrable commitment to the bid by stakeholders at all levels in Saudi Arabia, ranging from government to the private sector, is clearly evident and ensures a strong legal framework for seamlessly and successfully organizing the FIFA World Cup in ten years’ time,” FIFA said.

Still, staging the tournament in Saudi Arabia is sure to delight millions of young Saudis, who passionately follow the sport. Thousands crossed the border and headed to Qatar to watch their team at the World Cup where the country’s national team pulled off one of the biggest shocks in tournament history, beating Lionel Messi’s Argentina, the team that went on to win the competition, in the first game.

“They have a genuine fan base that really cares,” ” said Mr. Krieg, the professor.

Ismaeel Naar contributed reporting from the United Arab Emirates.