The king, who is in the company of his 10th wife, Inkhosikati LaNtentesa, arrived in Havana on Sunday night.
On Monday he toured the Centre for Genetic Engineering and Biotechnology and various health institutions.
He is due to attend a state banquet hosted by Cuban President Miguel Díaz-Canel on Monday night before his departure to eSwatini on Tuesday.
Cuba and eSwatini have healthy bilateral relations, with the former sending a delegation of medical experts to the southern African country each year to conduct free surgeries on patients.
Currently, there are 11 emaSwati who are undergoing medical training in Cuba, courtesy of the Cuban government.