This study analyses the activities of the local and regional authorities (LRAs) from EFTA countries in Brussels. It generates new and up-to-date knowledge on the mobilization in the EU by LRAs from EFTA countries; it enriches the literature on multi-level governance in the EU, so far mostly confined to the mobilization of LRAs from EU countries; and it contributes to the debate on lobbying in the EU by third-country actors. This research identifies three scenarios of engagement with the EU institutions: the first in which the Brussels offices predominantly engage in information-gathering and networking/liaison activities; the second in which the LRAs also engage in lobbying the EU; and the Swiss Cantons, that are fully integrated in the Swiss Mission to the EU.