A criminal court ordered on Sunday the release of journalist Amr Badr on EGP 5,000 bail pending investigation, lawyer Khaled Ali announced on his official Twitter account.
Badr has been facing charges of spreading false news, inciting the public, and plotting to overthrow the regime.
The accusations are linked to articles published on the government's April deal with Saudi Arabia to transfer the authority of the two Red Sea islands of Tiran and Sanafir to the kingdom.
Badr, editor-in-chief and founder of Yanair (January) website, and journalist Mahmoud El-Sakka, who works for the same website, were arrested at the Press Syndicate headquarters in late April as they were staging a sit-in to protest against their arrest warrants as well as the storming of their homes by security forces.
Badr and El-Sakka are veterans of both the 2011 revolution that toppled longtime autocrat Hosni Mubarak and the Tamarod movement that spearheaded demonstrations to oust Mubarak's successor, Islamist president Mohamed Morsi, in 2013.
El-Sakka is due back in court for a renewal of detention hearing on 7 September.
Their arrest in the union's headquarters caused an uproar amongst journalists and activists.
The journalists' union charged that police storming of the union's headquarters broke press law that mandates that the police must obtain the approval of the general prosecution before entering the premises of the union, and can only do so in the presence of the head of the union.
The interior ministry has denied its actions broke the law, arguing that officers followed all legal procedures while carrying out the arrests and they had secured the approval of the prosecution prior to entering the union headquarters.
Lawyer Khaled Ali told Ahram Online that other than El-Sakka, at least ten activists in Cairo - and several others from different governorates - out of several hundreds who were arrested in relation to demonstrations against the government's island deals are still detained.
The Street Children (Atfal Shaware) band members, arrested for a video released in protest at the deal, also remain in detention.