Working memory plays a key role in cognition as it is a major predictor of a wide range of higher order abilities and behaviors typical to daily life. Shorter versions of the complex span tasks (CSTs) have been recently developed, allowing for the reduction of test administration time without affecting validity and reliability in the measurement of working memory capacity (WMC). However, these short versions have not been validated for the Spanish-speaking population. The present work aimed to validate an English version of the shortened CSTs into Spanish in a sample of 325 university students (40% female; mean age = 21.04; SD = 2.80). Cronbach’s coefficient alpha was computed for each complex span task as an index of internal consistency. Validity evidence was evaluated by comparing participants’ scores on the three shortened complex span tasks (operation span, symmetry span, and rotation span) with two measures of reasoning ability (Raven’s Advanced Progressive Matrices and Number Series) and using confirmatory factor analysis. Results indicated that the short version of the Spanish complex span has satisfying qualities for assessing WMC in a sample of university students, which is an initial step toward providing a valid and standardized method for assessing WMC in the Peninsular Spanish-speaking population.