Research on child English as a second language (ESL) learners has shown the benefits of task-based interaction for the use of different negotiation of meaning (NoM) strategies, which have been claimed to lead to second language learning. However, research on child interaction in foreign language settings is scarce, specifically research on a new prevalent methodology in Europe, content and language integrated learning (CLIL). The present study focuses on mainstream and CLIL English as a foreign language (EFL) learners' oral interaction while they completed a guessing game and a picture placement task. The researchers analysed the oral production of seventy-two 9- to 12-year-old children (in age- and proficiency-matched dyads) to examine the conversational strategies that were employed in both tasks. Findings indicated that younger learners negotiated for meaning more, and mainstream learners resorted to more conversational strategies than CLIL learners. Furthermore, task-based differences in the NoM strategies seemed to depend on age and instructional setting. The results seem to indicate that age, instructional setting, and the tasks in which these EFL learners were engaged had an impact on the NoM strategies they employed in task-based interaction.