Passing the San Lorenzo area, the trunk begins to skirt the coast through the city of Esmeraldas and the towns of Atacames and Sua.

In Esmeraldas, the route links with the start of the Northern Transverse (E20), which connects with Santo Domingo in the Province of Santo Domingo de los Tsáchilas and the capital, Quito, in the province of Pichincha.

In Manta, the backbone connects to the Central Cross (E30) linking it to Portoviejo, Manabi and Latacunga, Cotopaxi, the two east.

Once in the Province of Santa Elena, E15 passes through a number of villages and seaside resorts of high attraction as Ayampe, Olon, Montañita, Ayangue Ballenita, etc.

The combined route, which carries the designation E15 / E40, extends southwest direction, culminating in the city of Salinas in the west of the Punta de Santa Elena (Point westernmost end Ecuador continental).