Résumé : Aquatic ecosystems are among the most impacted by biological invasions and eradicating invasive species from these systems proves to be very challenging. Thus, it is crucial to prevent new introductions, and the secondary spread of invasive alien species (IAS) already present through a collective effort of all water users. Adopting biosecurity measures is an efficient way to decrease the unintentional transportation of IAS on equipment due to human activities. To inform the development of the first biosecurity campaign for Belgian anglers, a national online survey was conducted during the spring of 2023, generating over 3000 individual responses. This study had two main objectives: 1) to gain a better understanding of the risk of IAS transport by recreational anglers, and 2) to inform the development of a communication campaign by assessing anglers’ awareness and perception of the issue of biological invasions. The results revealed a major risk of anglers inadvertently introducing IAS into previously uninvaded ecosystems, either through the unintentional transfer of organisms during a single outing (25% of anglers) or by transporting them from abroad (45% of anglers). This risk is compounded by the fact that only 8% of anglers adhere to the full check-clean-dry routine after each trip, and mobile anglers were not necessarily more proficient at cleaning their equipment. Additionally, some anglers admitted to occasionally releasing bait or translocating undesired species. Despite limited awareness of biological invasions, respondents generally had a negative perception of IAS. As a result, anglers could be considered an ally in the fight against IAS. The results of this baseline survey will inform future action plans to reduce invasion levels and raise awareness among the angling community in Belgium. It will aid in designing adequate messages, efficiently reaching the target audience, and assessing the campaign’s influence on angler habits and awareness.