Abstract Recently, there has been considerable research concerning the effect of CLIL on English language learners’ competence. However, it remains unclear if the positive effects found are due to CLIL or to time. To clarify this issue, this paper focuses on the vocabulary output of CLIL and non-CLIL EFL learners after an equal number of hours of English exposure. The objectives were twofold: (1) to ascertain whether the CLIL group retrieves a higher number of English words than the non-CLIL group; (2) to determine whether the two groups produce the same or different words. The sample comprised 70 Spanish EFL learners in their 8th and 10th year of secondary education. The data collection instrument was a lexical availability task consisting of ten prompts. The data were edited, coded, and subjected to quantitative and qualitative analyses. The results showed that the CLIL group retrieved a higher number of words than the non-CLIL group. However, both groups exhibited similarities concerning most and least productive prompts, first word responses, word frequency, and word level. The findings suggest a need to conduct equal comparisons of CLILs and non-CLIL groups as well as to examine the task effect, and the vocabulary input received by learners.