Although English and Spanish both have the voiceless stops /ptk/, they differ in VOT; English has long-lag voiceless stops and Spanish has short-lag. This difference means that native English-speaking learners of Spanish are likely to transfer the long voice lag typical of their first language (L1) to Spanish voiceless stops. This study measured the VOT of 20 native English-speaking learners of Spanish, each with a length of residence (LOR) in a Spanish-speaking country of almost 2 years. The study participants were found to produce voiceless stops intermediate to the averages of their L1 (American English) and L2 (Spanish), with some speakers producing voiceless stops with the range observed for Spanish. A significant main effect on VOT was found for all the variables of linguistic context tested: place of articulation, word-initial vs. -internal position, stress, preceding segment and following segment. A significant main effect was also found for speech style, percentage of communication done in Spanish with native Spanish speakers while abroad, years of formal L2 instruction prior to stay abroad, and time spent each week speaking Spanish with native speakers since their return home. While the extra-linguistic variables are correlated with more target-like VOT, the amount of communication done in the L2 with other native English L2 learners of Spanish was correlated with longer VOTs, i.e. less target-like VOTs, possibly due to reinforcement of L1 transfer habits.