Unión Adarve was the result of a merger of two teams from Barrio del Pilar, ADC Adarve and Unión Barrio del Pilar. After several seasons in the Regional divisions, the club promoted to Tercera División in 2007 by finishing in the third position of the 2006–07 Regional Preferente.
In 2013, Unión Adarve qualified for the first time to the promotion playoffs, but was eliminated by CD Tropezón in the second round. After several other attempts, promotion was finally gained in 2017 with an away goals victory after a 4–4 draw with Atlético Malagueño.
In the club's first Segunda División B campaign, they also competed for the first time in the Copa del Rey, where they defeated neighbours CF Rayo Majadahonda 1–0 away in the first round on 30 August. In the next round away to UD Logroñés a week later, they lost 8–7 on penalties after a goalless draw.