US Secretary of State John Kerry looked on as the US flag was raised at the country's newly reopened embassy in Havana on Friday.
Cuban dissidents were not invited to the embassy ceremony, avoiding tensions with Cuban officials who typically boycott events attended by the country's small political opposition.
The US State Department said it had limited space at what it called a government-to-government event, and has invited dissidents to a separate afternoon flag-raising at the home of the embassy's chief of mission.
During the ceremony, Kerry switched to Spanish and said the time had come for the US and Cuba to be neighbours, not enemies or rivals.
Political change remains a taboo topic in Cuba, despite a series of economic reforms and the reestablishment of diplomatic ties with the US under President Raul Castro, who took over from his brother Fidel.