San Carlos (Spanish pronunciation: [saŋ ˈkaɾlos]) is the capital city of the municipality of San Carlos and of the Río San Juan Department of Nicaragua.

The city proper has a population of roughly 17,000, while the city and surrounding communities (Comarcas) contain a population of 52,055 (2022 estimate).

The Solentiname Islands in Lake Nicaragua are part of the Municipality of San Carlos.

The municipality is divided into the following comarcas: San Carlos is twinned with:

This Nicaragua location article is a stub.