Puerto Rico Highway 3 (PR-3) at nearly 100 miles long, is the second-longest highway on Puerto Rico. It connects the San Juan neighborhood of Río Piedras to downtown Salinas indirectly around the eastern coast of the island. Highway 3 ranges from a three lane urban avenue in San Juan to a one lane rural road past Fajardo. While other roads connect San Juan, it runs the coastline of Puerto Rico east of San Juan, beginning in Río Piedras near Santurce and goes to Fajardo where it goes south paralleling the coastline to Humacao and Maunabo. It goes up to a mountain-scenic route and goes west to Salinas, where it meets PR-1.

Puerto Rico Highway 2 (PR-2) is a road in Puerto Rico that connects the cities of San Juan and Ponce. At 156 miles (230 km) long, it is Puerto Rico's longest singled-signed highway.