The trip will be Xi's first known visit outside mainland China since January 2020 after the COVID-19 outbreak.
He will also attend the inaugural ceremony of the sixth-term government of Hong Kong, state news agency Xinhua reported.
John Lee will become the city's new leader on July 1, replacing Carrie Lam, who oversaw a tumultuous recent period in the territory, with anti-government protests and COVID-19.
Xi also oversaw the swearing-in of Lam in 2017, when he was in Hong Kong to celebrate the 20th anniversary of the handover.
Uncertainties over whether Xi would visit the former British colony had grown in recent weeks as new COVID-19 infections increased in the city, with two incoming senior officials among the latest cases.
China adopts stringent COVID policies and travel restrictions which aim to eradicate all outbreaks, at just about any cost, running counter to a global trend of trying to co-exist with the virus.
Critics said Hong Kong's 25th handover anniversary is significant to China which sees the city stabilising from the mass pro-democracy protests in 2019, after the implementation of the national security law and electoral reforms that ensure only "patriots" can work in the government and lawmaking body.
A former top policeman turned civil servant, Lee has pledged to maintain a firm grip on the city under the security law, in line with China's sovereign interests.
Hong Kong was handed over to China on July 1, 1997, after 156 years of British colonial rule.
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