Rahaf Mohammed al-Qunun was already en route to Toronto late Friday night (Thailand time) when the prime minister made the surprise announcement, after officials had previously given heavy hints she was bound for Australia.
“Canada has been unequivocal that we’ll stand up for human rights and women’s rights around the world,” Trudeau said. “When the United Nations made a request of us that we grant al-Qunun’s asylum, we accepted.”
The move may further strain Canadian relations with the kingdom that went sideways last August over Ottawa’s rights criticism of Saudi Arabia, prompting Riyadh to expel the Canadian ambassador and sever all trade and investment ties in protest.
Canada had already sparked fury in Riyadh by demanding the “immediate release” of jailed rights campaigners, including Samar Badawi, the sister of jailed blogger Raif Badawi, whose family lives in Quebec.
Qunun’s attempt to flee the ultra-conservative kingdom was embraced by rights groups as a beacon of defiance against repression.
She deleted her entire contentious Twitter account hours before departure for Canada. Others reconstituted it and back-filled it with old and new messages, but the account no longer has her name or photo.
Thai Immigration Bureau authorities initially threatened to deport her after she arrived in Bangkok from Kuwait last weekend.
But armed with a smartphone and hastily opened Twitter account, she forced a U-turn from Thai immigration police who handed her into the care of the UN's refugee agency as the #SaveRahaf hashtag bounced across the world.
Qunun alleged that she was abused by her family – who deny the allegations – and rights groups also said she had renounced Islam, risking prosecution in Saudi Arabia.
Rahaf first said she was aiming for Australia where officials had suggested they would give serious consideration to her claim for asylum, which was endorsed as legitimate by the UNHCR on Wednesday.
But late Friday Thailand’s immigration police chief said a smiling and cheerful Rahaf was bound for Toronto and had left on a flight after 11pm, Thailand time.
“She chose Canada... Canada said it will accept her,” immigration chief Surachate Hakparn told reporters at Suvarnabhumi.
“She is safe now and has good physical and mental health. She is happy.”
Rahaf left from the same airport where her quest for asylum began less than a week ago in a swift-moving process that defied most norms.
On Friday afternoon Rahaf posted a final cryptic tweet on her profile saying “I have some good news and some bad news” – shortly after her account was deactivated in response to death threats she had faced, her friends said.
“Rahaf received death threats and for this reason she closed her Twitter account, please save Rahaf life,” tweeted supporter @nourahfa313, who has flanked Rahaf's social media campaign with her own updates on Twitter.
Rahaf’s swift use of Twitter saw her amass more than 100,000 followers within a week, highlighting her plight at a time when Saudi Arabia’s human rights record is under heavy scrutiny following the murder of journalist Jamal Khashoggi last year.
Her deployment of social media allowed her to avoid the fate of countless other refugees who are quietly sent back home or languish in Bangkok detention centres.
She refused to see her father who travelled to Thailand and expressed opposition to her resettlement.
Gen Surachate said her father and brother were due to return home on a flight in the early hours of Saturday.
Although her asylum case moved fast the final manoeuvres that led to her flight to Canada remain a mystery.
Australia had dropped strong hints it would accept her after the UN urged the country to do so and it remains unclear why the resettlement location changed.
On Thursday its foreign minister said Canberra was still assessing the request.
Earlier, Gen Surachate told reporters Friday that “two or three” countries were ready to offer her asylum.