We tested whether second language (L2) learners rely more on explicit memory during structural priming at lower than at higher proficiency levels (Hartsuiker & Bernolet, 2017). We compared within-L2 priming with lexical overlap in 100 low and 100 high proficiency French L2 speakers under low versus high working memory load conditions induced with a letter series recall task presented between primes and targets. The high load condition would prevent explicit recall of primes during target production. Both groups primed more under low than high load. The effect of load was similar across groups, but exploratory analyses with proficiency as a continuous variable suggested that, with increasing proficiency, participants primed less under high load. We discuss how these findings support the idea that learners exploit explicit memory more during priming in early versus later stages of acquisition. Overall, this study showed that explicit memory influences syntactic processing across the L2 learning trajectory.