If you are starting your camino in Oviedo be sure to leave enough time to visit the Cathedral, which is the origin of the camino itself. It is also the place to pick up your credential (pilgrim passport) which will cost you 2.5€ but will include a visit to the Camara Santa, the oldest part of the Cathedral which was originally built to secure relics.
The greater Oviedo area is home to more pre-Romanesque architecture than any other place in Asturias; including the Iglesia de San Julián de los Prados, Santa María del Naranco and San Miguel de Lillo. These last two are not in the city center, but instead require a small detour when leaving Oviedo on the way to Santiago.
On the other end of the spectrum is the ultra-modern Palacio de Congresos by Calatrava, and in between the oldest and the newest are dozens of churches and civic buildings of note. The Monasteries of San Vicente and San Pelayo are the most noteworthy.
When Oviedo was founded in 761 it was all but deserted apart from two monks; Fromestano and his uncle Máximo. These two dedicated their church to San Vicente, and 20 years later it would grow to become a monastery. In that monastery was born the future King Alfonso II, during whose reign would be discovered the remains of Santiago. It was he that first made the pilgrimage to Santiago, and in so doing the mountainous path between Oviedo and Santiago became known as the Camino Primitivo.
The road out of Oviedo is notoriously confusing. To make matters worse, there are too many shells on the ground to be helpful, especially in the center. They mark several of the caminos into, and out of, Oviedo. There is no distinction between the two directions.
This is how it is done:
1. With the main facade of the Cathedral to your back, walk to the opposite end of the plaza and take the exit on the right. This is the Calle San Francisco.
2. San Francisco ends when it meets Calle de Uría (350m from Cathedral). Turn right and follow Calle de Uría. For the first 250m, the Parque de San Francisco will be on your left. Stay on this road, regardless of arrows or shells. It is about 700m long and ends at the train station.
3. At the train station, turn left along the Calle de la Independencia. Stay on the right-hand side of the road. You will pass 7 cubist looking apartment buildings before the sidewalk turns sharply back to the right. Follow the turn and cross the road towards another cluster of 4 similar buildings with a plaza in front. From here it is safe to follow the arrows.
4. At the end of the plaza is a roundabout. Cross to the left (clockwise) twice and turn left along the Calle de la Argañosa. When it turns to the left (700m) you should turn towards the right, looking out for the pedestrian bridge which crosses the train tracks.
5. The arrows from here zigzag you through new development which ends quickly. By the time you get to an urban looking track and have left Oviedo behind, you will have covered about 3.6km.