Soft law instruments account for a sizable share of EU legal acts, with growing importance over time. Yet, while the implementation of hard EU law has been widely studied, little is known about the use of EU soft law at the national level. In the article, it is firstly argued that the type of soft law instrument will affect national usage. Administrators and judges may welcome interpretative guidelines to complicated pieces of legislation, while more open-ended instruments may be ignored. It is further argued that the maturity of the policy field matters. National actors in mature policy fields will be routinely exposed to EU rules and they are socialized into responding to impulses from Brussels. The article probes the plausibility of these expectations in case studies on the use of EU soft law instruments by German administrations and courts in four policy fields: financial market regulation, competition, environmental protection and social policy.