But the renewed access on Wednesday may be short-lived.
Late in August, Justice Alexandre de Moraes ordered X blocked nationwide after months of tension with the site's billionaire owner Elon Musk over free speech, far-right accounts and misinformation. De Moraes also set fines for anyone using virtual private networks, or VPNs, to access the platform.
That rendered X effectively inaccessible in the country until Wednesday, when an Associated Press journalist was among those who regained access. The number of X posts made in Brazil rose from 939,000 Tuesday to more than two million by late afternoon on Wednesday, data analysis company Bites said.
Experts examining X's IP addresses - numeric designations that identifies sites' location on the internet - said there are indications the company has begun routing users through the servers of Cloudflare, a content delivery network, en route to its own.
"The service that Elon Musk's social network has started using works like a 'digital shield' that protects the company's servers," Pedro Diogenes, Latin America's technical director for CLM, a distributor that focuses on cybersecurity.
It acts as a proxy between users and X's servers, filtering traffic and preventing the original IP address from being recognised, Diogenes told the AP.
Brazil's telecommunications regulator Anatel said it is looking into the situation and will report its findings to the Supreme Court, noting that there has been no change to de Moraes' ruling. A panel of fellow justices later upheld his decision, though it hasn't yet gone before the court's full bench. His fine for VPN users in particular has faced blowback, including from the nation's bar association.
The Supreme Court declined to comment on possible actions it could take. X said on its platform that the shutdown in Brazil affected service to Latin America as a whole, so it swapped network providers.
"This change resulted in an inadvertent and temporary service restoration to Brazilian users," the Wednesday evening statement said.
"We expect the platform to be inaccessible again shortly."
Earlier Wednesday, former President Jair Bolsonaro celebrated the return of the social network with a post from his account. He has sided with Musk in the feud with de Moraes and sought to portray the ban as censorship from an overzealous judge.
