Haidar had been on hunger strike at Lanzarote Airport on Spain’s Canary Islands for more than a month.
That began after Morocco refused to let her back into the country after saying she hadn’t filled out the necessary paperwork.
Ahead of her return, Haidar hailed the U-turn by Morocco’s authorities. ‘‘This is a triumph, a victory for international rights, for human rights, for international justice and for the cause of the Saharan people,” she said.
Activists, most notably Haidar, have been demanding independence for Western Sahara since Spain pulled out of its African colony in 1975 and Morocco annexed the territory.
There were celebrations among her supporters in Lanzarote at the news of her return.
The stand-off has proved politically embarrassing for Spain’s government, with many accusing it of failing to handle the crisis properly.
Africa's last colony
Since 1975, three quarters of the Western Sahara territory has been illegally occupied by Morocco. The original population lives divided between those suffering human rights abuses under the Moroccan occupation and those living in exile in Algerian refugee camps. For more than 40 years, the Saharawi await the fulfilment of their legitimate right to self-determination.