Near Field Communication (NFC) is an emerging technology for mobile interaction with everyday objects and associated digital resources. Apart from simple interactions with single tags, NFC has the potential for more elaborate interactions with physical objects that comprise multiple tags and serve as physical user interfaces (UI). This paper investigates the design of mobile and physical UIs for the interaction with multiple NFC-tags. It focuses on three basic interactions that qualify for multi-tag interactionthe navigation between parts of an application, the selection of items and the combination of items. Two user studies compare different configurations of mobile and physical UIs for these interactions in order to evaluate the allocation of application features and UI elements to mobile devices and tagged objects. The results advocate the continuous interaction on the latter, instead of splitting interactions between mobile and physical UIs.