Different methods to acquire a language can contribute differently to learning success. In the present study we tested the success of L2 stress contrasts acquisition, when ab initio learners were taught or not about the theoretic nature of L2 stress contrasts. In two 4-hour perceptual training methods, French-speaking listeners received either (a) explicit instructions about Spanish stress patterns and perception activities commonly used in L2 pronunciation courses or (b) no explicit instructions and a unique perception activity, a shape/word matching task. Results showed that French-speaking listeners improved their ability to identify and discriminate stress contrasts in Spanish after training. However, there was no significant difference between explicit and non-explicit training nor was there an effect on stress processing under different phonetic variability conditions. This suggests that in L2 stress acquisition, non-explicit training may benefit ab initio learners as much as explicit instruction and activities used in L2 pronunciation courses.