The Paseo de la Princesa takes you to the San Juan Gate, which is the city's oldest. Here, you can pick up the Paseo del Morro. This hike, only about a mile, follows the walls of the old fortress of El Morro.
Continuing where the Paseo de La Princesa ends, the Paseo de El Morro takes a winding path between the colonial wall and the shore all the way to the base of Castillo San Felipe del Morro. Detracting considerably from this otherwise unspectacular walk are the countless feral cats prowling the rocks.