This study explores the development of L2 phraseological knowledge, focusing on the relationship between L2 proficiency and the use of adjective-noun combinations from the perspective of collocation density and association strength. While a growing body of evidence suggests that more advanced L2 production tends to be characterised by (i) a greater collocation density and (ii) more strongly associated collocations, several studies did not find this trend. The present study draws on the British Council-Lancaster Aptis Corpus and data from four proficiency levels (A2-C of the CEFR) to test a hypothesis about the direction of collocation development in order to contribute to a systematic advancement of knowledge about the development of productive L2 collocation use. The study replicates some of the key findings from previous research, confirming that these trends are generalisable to different samples of L2 speakers and across different modes of communication.