A handful of studies have used Facebook’s advertisement platform – Facebook Ads Manager – to recruit migrants to online surveys. The main challenge facing migration scholars in designing effective advertisements has been to identify and accurately target migrants on Facebook. Researchers have used proxies, such as users’ previous residence abroad, language(s) or interests, to infer their migration status. Despite some progress, there remains a need to better document and reflect critically on the accuracy of targeting migrants using such proxies. Contrary to studies which relied on users’ previous residence abroad, this study used migrants’ language (Polish) to target and recruit survey participants from among Polish migrants in Norway, Sweden and the UK. Focusing on a single migrant group across three countries, the goal of this article is to assess the accuracy of a targeting strategy which relied primarily on users’ command of a language as an indicator of their migration background. Comparing the results against official migration statistics and the results reported in similar studies, the article provides a compelling case for researchers to prioritise users’ language, rather than previous residence abroad, as the proxy for migration background for migrants whose language, such as Polish, is confined to the borders of a single nation state.