The environmental science-policy interface, consisting of dynamic interactions between various actors, is increasingly an object of study. In this interface, new types and kinds of boundary organisations are emerging and new types of knowledge brokering are taking place. Given the increasing calls for more evidence-based policy, it is pertinent to examine what type of SPI can be identified at the national level, how knowledge is brokered in it and how boundary organisations function and are positioned within the network. To do this, we utilise a mixed method approach, combining a survey questionnaire and interviews as data collection methods with social network analysis and qualitative content analysis to examine the national science-policy interface in the environmental domain in Finland. Our results show a centralised network with weak reciprocal links. The network is centred more around knowledge brokers and users than knowledge producers. In this network, knowledge is mainly brokered through media and personal communication, with no single actor group assuming responsibility. The boundary organisation studied here engages in brokering activities and actively creates venues for knowledge brokering. Our findings are in line with previous research, demonstrating the need for further strengthening of not only the structural foundations of the science-policy interface, but also of the actors engaging in knowledge brokering.