There has been growing interest in regional policies that stimulate interactions between different sectors, often based on the concept of ‘related variety’. The identification and development of new cross-sectoral growth trajectories has been described elsewhere as building ‘regional development platforms’. This article contributes to conceptual debates about cross-sectoral regional development platforms and provides an empirical analysis of attempts to create and develop such a platform. From a conceptual perspective we argue that the notion of related variety can help policymakers to identify potential combinatorial platform opportunities, but may overestimate the ability of ‘related’ actors to collaborate together in innovative ways, because knowledge is embedded in practice and the process of ‘combining’ knowledge in new activities is therefore challenging. The paper illuminates the development of cross-sectoral platforms by examining the creation of new activities from a practice perspective that directs attention to the everyday activities, routines and understandings that constitute the ‘doing’ of economic development. We explore the development of a cross sectoral platform in the North Jutland region of Denmark, which integrates actors from the food and tourism sectors into a new food-tourism platform. We identify the dominant forms of the practices of producing food, retailing, catering, and promoting tourism, and then consider the ways in which these have changed in response to new cross-sectoral initiatives. The analysis shows that some aspects of practice are easier to change than others, and we conclude that an analytical approach inspired by practice theory can identify the requirements in terms of micro-level change in the practices of actors that is required for an initiative to succeed.