The educational system in Cuba has achieved great results in all the educational levels.
Ms Rubio, a delegate from Cuban teachers' union SNTECD, addressed the National Union of Teachers conference in Cardiff on Sunday.
She explained the massive progress made since 1959, when the Cuban revolution inherited a country where illiteracy was running at 25 per cent.
Now, 99.8 per cent of Cubans can read and write.
After the revolution, literacy brigades of students were sent to the rural areas to educate the peasants, who had been kept in poverty and ignorance under capitalism.
All schools on the island were made free and available to all. The government formed youth brigades that cut illiteracy to 3 per cent in a few years.
Despite the long-running US blockade of Cuba, 99 per cent of Cuban children now attend free compulsory schooling to secondary level. And there is no private education.
Class sizes have been reduced from 30-40 students to 15-20. Discrimination on the grounds of race, gender, religious and political beliefs has been eliminated.
Ms Rubio said that "Cuba is unique in the developing world" as it has already achieved its Millennium Development Goals on education.
In 1959 there were three universities in the country. Now there are over 45 as Cuba seeks to make college education universally available.
"We are taking the university to each single province and locality to allow students to study in their municipalities," she said.
Cuban TV also broadcasts the University For All programme and there is a communal University for the Elderly.
Cuba has also shared the benefits of its education system with other countries. The Latin American School Of Medicine, founded in 1998, offers 1,500 free scholarships every year to students from Latin America, the Caribbean, north America and Africa.
Cuba's literacy programme Yo Si Puedo - Yes I Can - is in use in many countries, most notably Venezuela and Bolivia, where it was the basis for a campaign that has eradicated illiteracy in a few years.