But while the latest detentions have drawn criticism, they come amid a much wider crackdown on those who have called for changes in the absolute monarchy or fail to publicly support the prince.
While engaging in an international charm offensive to publicize his sweeping plans to transform Saudi society and economy, the 32-year-old prince has also presided over waves of detentions — of intellectuals and clerics, officials and billionaire businessmen accused of corruption, and now the women's rights activists.
"We have seen through the crackdown on activists, writers and social media users that the Saudi Arabian authorities have no tolerance for dissent, peaceful calls for reform, or anyone who dares to speak out against the country's domestic or foreign policy," said Dana Ahmed, Amnesty International's campaigner for Saudi Arabia.
Even so, the timing of the latest moves — just weeks before the much-vaunted lifting of a ban on women driving — as well as the harshness of an accompanying media campaign, surprised seasoned Saudi observers.
"What I find particularly galling is the emergence in the Saudi press of claims these guys were traitors," said Michael Stephens, a Middle East expert at the Royal United Services Institute, a think tank in London. "I just don't know why they thought this was OK."
The announcement of the activists' arrests last week was accompanied by reports in state-linked media that those being held had offered financial support to "overseas enemies" and had suspicious contacts with foreign entities. A hashtag dubbing them "agents of embassies" with the word "traitor" stamped on their faces also began circulating on social media.
This was a marked contrast to previous mass arrests.
"It has been really shocking and really unprecedented," said one prominent Saudi women's rights activist who spoke on the condition of anonymity out of fear of reprisals.
"We haven't seen this sort immediate condemnation and smear campaign against anyone who was arrested," she said, adding that she was very worried about friends and comrades who were being held without access to families and lawyers.
Among the detainees identified by campaigners were Eman al-Nafjan, Loujain al-Hathloul, Aziza al-Yousef, Ibrahim al-Modeimigh, Mohammed al-Rabea and Aisha al-Mana. Al-Mana and two other veteran woman's rights campaigners were released within days, according to Amnesty International, which speculated that they had been let go on medical grounds.
Interior Ministry officials contacted in Saudi Arabia did not respond to a request for comment, referring NBC News to a newly created Home Security department, for which they did not have contact information.
The country's embassy in Washington also did not respond to requests for comment.
Social changes initiated under the crown prince, such as allowing cinemas and concerts, pushing for women's inclusion in the workplace and allowing some gender mixing, have been hailed as proof that bin Salman is steering the conservative country in a progressive direction and away from religious zealotry.
While Saudi-U.S. ties grew strained under the administration of President Barack Obama, President Donald Trump and Jared Kushner, his son-in-law and senior adviser, have embraced the crown prince as a close and crucial partner in the administration's Middle East strategy. Trump went to Saudi Arabia in his first foreign trip as president.
Meanwhile, bin Salman has been hailed by some commentators, journalists and Western business leaders as a welcome reformer forcing through desperately needed changes in the conservative country. The crown prince's foreign trips, as well as high profile events he has sponsored in the country, have been accompanied by the announcement of billions worth of trade deals.
At one of these events on Oct. 24, bin Salman announced he would crackdown on extremists and promote a more moderate form of Islam.
He later told The Atlantic magazine that he was trying to "encourage the power of law."
"We would like to encourage freedom of speech as much as we can, so long as we don't give opportunity to extremism," the prince said. "We can improve women's rights, improve the economy."
But according to rights campaigners, the recent arrests followed a pattern predating the accession to the throne of the crown prince's father, King Salman, in January 2015: activists push for reform, followed by a crackdown and then by more limited progress driven by the royal household.
This strategy "sends a message that anyone who is trying to exist or be committed to activism through the international media will be accused or treated this way: as a traitor," the activist said.
Others seen to fall afoul of the royal household's line have also suffered. One example is Salman al-Awda, a hugely popular cleric who called for democratic reform. He was among a handful of clerics and intellectuals to be detained in September and has been held in jail since.
While the recent arrests follow a pattern, the situation has gotten much worse since the emergence of the crown prince as the power behind the throne, according to Amnesty International.
"Many activists who were on trial were sentenced in the past few months to lengthy prison terms before the counterterror court and activists who were already sentenced were arrested in September 2017 to start serving their sentences," Amnesty's Ahmed said.
The Saudi activist, Stephens and others speculated that the arrests of the women's rights' campaigners could also have been driven by pressure to appease religious conservatives made uneasy by the swift pace of recent social and economic changes.
Regardless of the crown prince's intentions, the arrests run counter to the international public relations campaign showcasing Saudi progress, according to Jane Kinninmont, deputy head of the Middle East and North Africa program at Chatham House, a London think tank.
"Some Western observers have been happy to turn a blind eye to the arrests of clerics or commentators said to be Islamist, apparently thinking — even if they don't say it publicly — that an autocratic approach may be necessary to force through social change," she said.
"Arresting women who campaigned for exactly what the Saudi government is now implementing muddies the waters."