Working memory (WM) is a recognised component of executive function and has undergone scrutiny in terms of bilingual and monolingual performance comparisons. Research to date, however, has not consistently replicated the presence of bilingual advantage. The present study examined short-term (STM) and WM in immersion-educated children and a matched group of English monolingual controls. One hundred and twenty-one children participated, and differences in performance were examined in two age groups (7 and 9 years). Children performed two STM (digit recall, mazes memory) and four WM tasks (listening recall, counting recall, backwards digit recall, Mr. X). Results indicated largely equivalent performance on the STM and WM tasks administered. Verbal STM and WM performance in L1 (English) and L2 (Irish) was then examined within the bilingual sample only. Results indicated largely equivalent performance across languages for both age groups, with language dominance effects emerging in one verbal WM task (listening recall) only. Overall, our results suggest that bilingualism does not confer advantages for WM. Implications for the assessment of STM and WM in bilingual children participating in a full immersion education programme are discussed.