It runs from its north end at its intersection with PR-22 (known as Expreso José de Diego) in San Juan to its south end in Río Piedras where it intersects with PR-1.

[3] PR-18 connects PR-52 to PR-22 and intersects with Jesús de Piñero Avenue (PR-17), Franklin Delano Roosevelt Avenue (PR-23), which grants access to Plaza Las Américas, and Domenech Avenue.

The combined route of PR-18 and PR-52 is coterminous with the unsigned Interstate Highway PRI-1.

[citation needed] The entire route is located in San Juan.

This Puerto Rico road-related article is a stub.