Since mobile telecommunications technology evolved significantly over the past 10 years, an adaptation of the legislation to limit exposure to electromagnetic radiation from transmitting antennas seemed indispensable. Given the forthcoming roll out of a widely available 5G network, this called for an exposure assessment of the additional 5G NR base stations before the deployment. Therefore, in 2019, the Flemish Department of Environment & Spatial Development investigated the roll out of 5G antennas, in addition to the existing telecom antennas, and the implications on exposure and the new legislation. A worst-case simulation was set up, using the maximum possible power for the existing antennas as well as for each of the added 5G antennas. This paper presents the results of the simulations for three locations that are representative of Flanders: these sites are urban or rural or a combination of both. We can conclude that based on the simulations the new legislation, adopting the precautionary principle, manages to limit exposure to electromagnetic fields from transmitting antennas as well as allowing the roll out of 5G in Flanders.