Answer
Yes. The historic quarter of Colonia del Sacramento was inscribed on the UNESCO World Heritage List in 1995. Its value lies in the preserved urban fabric, where Portuguese and Spanish stages of development and their influence on planning and architecture are evident.
The status refers to a particular historic area, not the entire modern city. The main sights—Portón de Campo, Calle de los Suspiros, Plaza Mayor, the ruins, the basilica, the lighthouse, and small museums—can be conveniently explored on foot from the port.
Visitors should respect barriers and site rules: inclusion on the UNESCO list does not mean unrestricted access to every building. Check the opening hours of museums and the lighthouse before travelling, as the combined ticket and the range of open exhibits may change.