San Diego — officially the Santa Catalina quarter — is the northern residential section of Cartagena's walled city. While the southern quarter around Plaza de los Coches and the Torre del Reloj is more commercial and tourist-heavy, San Diego retains more of the character of a lived-in colonial neighbourhood. Streets are quieter, the houses are generally more elaborate, and the door knockers and carved wooden balconies are at their most varied.
The neighbourhood contains several good restaurants and boutique hotels in converted colonial houses, as well as the Iglesia de San Pedro Claver and the Naval Museum. Walking through San Diego in the late afternoon, when the light is low and the heat has eased, is one of the best ways to experience Cartagena's architectural heritage without the midday crowds.