After the team failed to qualified for the playoffs for promotion, it confirmed the transfer on 13 December 2011 that Herrera will join Chilean Primera División side Unión Española, signing a five-year deal.
On 25 January 2012, Herrera officially made his debut for the club in the Copa Libertadores First Stage of the first leg against Tigres and on 2 February 2012, he scored the first goal for the club in the match in the second leg which was 2–2, going through to the group stage.
In the Copa Libertadores, Herrera would score 4 more against Junior de Barranquilla, Club Bolívar (scored again) and Club Deportivo Universidad Católica (all four goals come in the group stage).
Herrera then provided assists in the Copa Libertadores in both leg against Boca Juniors which in both games lost.
In the Copa Libertadores, Herrera entered in the competition scoring 5 goals in 10 games.

In the opening season of Chilean Primera División, Herrera scored on his debut in a 2–0 win over Audax Italiano on 29 January 2012.
After 3 games without scoring, Herrera scored a brace in a 2–2 draw against Club Deportivo Universidad Católica on 26 February 2012 and scored in the next game on 3 March 2012 in a 3–1 win over C.D. Palestino which followed by the next game on 10 March 2012 in a 3–1 loss against CD Huachipato.
On 24 March 2012, Herrera scored twice and setting up a goal for Fernando Cordero in a 5–2 win over Deportes La Serena.
On 7 April 2012, Herrera scored and setting up a goal for Mauro Díaz in a 4–2 win over Colo-Colo.
On 21 April 2012, Herrera scored in a 2–2 draw against Santiago Wanderers.
On 28 April 2012, Herrera scored and setting up a goal for Braulio Leal in a 4–1 win over C.D. Universidad de Concepción.
After scoring 10 goals in the regular season, Unión Española won the qualification for the final round to be in fifth place.

In the Play-Offs Primera División Apertura Quarter Final first leg against Club Deportivo Universidad Católica, Herrera scored and setting up a goal for Cordero in a 3–1 win which the second leg was 1–1 draw.
At the end of Campeonato Apertura, Herrera was a joint-top scorer Sebastián Ubilla.
During his time at Unión Española, Herrera earned a nicknamed 'El Tanque' due to his physical, dribbler and rather fast, it has the characteristic mark of the essential goals of the right foot.
His first season at Unión Española led interests from French Champions Montpellier.
After the team failed to qualified for the playoffs for promotion, it confirmed the transfer on 13 December 2011 that Herrera will join Chilean Primera División side Unión Española, signing a five-year deal. On 25 January 2012, Herrera officially made his debut for the club in the Copa Libertadores First Stage of the first leg against Tigres and on 2 February 2012, he scored the first goal for the club in the match in the second leg which was 2–2, going through to the group stage. In the Copa Libertadores, Herrera would score 4 more against Junior de Barranquilla, Club Bolívar (scored again) and Club Deportivo Universidad Católica (all four goals come in the group stage). Herrera then provided assists in the Copa Libertadores in both leg against Boca Juniors which in both games lost. In the Copa Libertadores, Herrera entered in the competition scoring 5 goals in 10 games.
In the opening season of Chilean Primera División, Herrera scored on his debut in a 2–0 win over Audax Italiano on 29 January 2012. After 3 games without scoring, Herrera scored a brace in a 2–2 draw against Club Deportivo Universidad Católica on 26 February 2012 and scored in the next game on 3 March 2012 in a 3–1 win over C.D. Palestino which followed by the next game on 10 March 2012 in a 3–1 loss against CD Huachipato. On 24 March 2012, Herrera scored twice and setting up a goal for Fernando Cordero in a 5–2 win over Deportes La Serena. On 7 April 2012, Herrera scored and setting up a goal for Mauro Díaz in a 4–2 win over Colo-Colo. On 21 April 2012, Herrera scored in a 2–2 draw against Santiago Wanderers. On 28 April 2012, Herrera scored and setting up a goal for Braulio Leal in a 4–1 win over C.D. Universidad de Concepción. After scoring 10 goals in the regular season, Unión Española won the qualification for the final round to be in fifth place.
In the Play-Offs Primera División Apertura Quarter Final first leg against Club Deportivo Universidad Católica, Herrera scored and setting up a goal for Cordero in a 3–1 win which the second leg was 1–1 draw. At the end of Campeonato Apertura, Herrera was a joint-top scorer Sebastián Ubilla. During his time at Unión Española, Herrera earned a nicknamed 'El Tanque' due to his physical, dribbler and rather fast, it has the characteristic mark of the essential goals of the right foot. His first season at Unión Española led interests from French Champions Montpellier.
Emanuel Herrera