Research involving secondary school EFL learners has demonstrated that greater intensity of exposure, via CLIL lessons, yields notable benefits. However, studies in primary school are scarce and less optimistic. Furthermore, little is known about the effects of different degrees of CLIL intensity and of learners' exposure to Extramural English (EE) through formal or informal out-of-school activities. To address these gaps, this study examines the impact of CLIL and EE on the proficiency of 180 primary school learners of English (aged 10-11 years) divided into a high-CLIL (N = 78), a low-CLIL (N = 56), and a non-CLIL (N = 46) group. Results showed some advantages among high-CLIL learners, including higher scores and less intragroup variability, while no significant differences were observed between low-CLIL and non-CLIL learners. EE activities were common, with several weak but positive correlations found between EE and proficiency, particularly involving watching TV and reading, and mainly affecting non-CLIL learners.