This paper explores how border control regimes are linked to the local condition of the Christian conversion of Afghan and Iranian ‘transit migrants’ in Istanbul. It is argued that transit migration is a securitised category, which contains ‘undesirable’ migration flows in and around the borders of the EU. The stuck condition into which ‘transit migrants’ are thrown has opened up a missionary space claimed by Christian organisations through their provision of social and welfare assistance. This paper reports on field research among migrants and agencies in Istanbul. Evidence gathered reveals that a state of stuckness is read by the migrants themselves through a desirable/undesirable binary inflected with an orientalist logic: the border is no longer conceived only in territorial terms but acquires an identity dimension cutting through the population. In this context, Christianisation offers the possibility to leap across the binary opposition west/non-west, to land on the desirable ‘west’ side and thus to reconstitute the self as desirable.