There have been important changes in the United Kingdom’s (UK) fertility and immigration in the past decade, with rising period fertility and increasing shares of UK live births to foreign-born mothers. Understanding of the rates underlying these figures, however, is currently limited because the relevant data are not collected directly. In this paper, we estimate UK fertility rates by key countries of birth, for the 1997-2010 period. For recent migrants to the UK, we present analyses disentangling the timing of migration and fertility, and address short-term hypotheses of migrationfertility patterns. Own Child fertility estimates confirm that the fertility of the Polish group is relatively low, characteristic of that at origin. For young South Asian migrants, evidence is found for family formation related migration, with high proportions arriving to the UK childless and having births soon after arrival. For Polish women, this phenomenon exists at younger ages but is less common, and those in their early thirties more commonly bring their children to the UK with them