Nature-based solutions (NBS) can play a critical role in sustainability transitions in both urban and rural areas, but their uptake is hindered by a wide variety of barriers. While networks have been identified as a support structure for mainstreaming NBS, it is unclear what specific roles networks play in addressing the multiple barriers that NBS mainstreaming faces. Through qualitative research using focus group meetings and semi-structured interviews within two sectors in the Netherlands where attempts towards a nature-based transition are observed – i.e., agriculture and construction – we identify seven different functions through which networks address six specific barrier categories. We find broad network functions (e.g., knowledge sharing) that address multiple types of barriers simultaneously and targeted network functions (e.g., lobbying towards policy makers) aimed at alleviating one specific type of barrier. We also document that networks leave certain barriers unaddressed, such as technological and political barriers in the construction sector and social barriers in both sectors. Our results contribute to a more in-depth understanding of network function – barrier combinations for nature-based sustainability transitions, both in an urban and a rural context, which can help networks to further strategize and allocate their resources.