Entrepreneurial ecosystems (EEs) are currently a major theme of entrepreneurship research and policies designed to support entrepreneurship. However, the role of specific policy instruments in EEs often remains unclear. This paper contributes to research on that topic by analysing the role of start-up competitions (SUCs) in the contrasting German case study regions Berlin and Hanover. Based on 45 qualitative interviews with participants in two public SUCs, their organizers, and ecosystem experts, the role that the SUCs play in each EE is investigated. Both analysed SUCs serve as networking events that can be described as ‘anchor events’ for specific parts of their ecosystems. They provide strong support for participants and help local entrepreneurship support offices connect and allocate their resources efficiently. However, sub-networks of entrepreneurs and actors who are not connected to the SUCs are identified. The SUCs seem to work primarily for public actors, ‘solid’ entrepreneurs, and university spin-offs. International venture capitalists, wealthy business angels, and high growth firms are not involved in the competitions. Both analysed regions influence the perceived value of their competitions, e.g. in terms of the industrial expertise of jurors. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.