Over the last decade, additive manufacturing (AM) has grown and expanded throughout different areas of engineering applications and is currently finding its place in aerospace, maritime and land transport industry [1]. Harsh environments in which these structures are designed to operate put significant impact on their mechanical properties [2]. Analysis of environmental degradation is essential for the prediction of their performance and life in such environments. In addition, assessment of environmental degradation can be useful when comparing performance of AM materials with those produced more traditionally. This session welcomes contributions that deal with numerical and experimental aspect of environmental degradation of AM materials and structures. Environmental effects can include, but are not limited to: corrosive environment, high temperature environment, high radiation environment, chemical exposure environment, coupled environmental and mechanical loading, etc. Numerical modelling of environmental degradation is of special interest, but also the experimental studies that serve as a basis or verification for numerical models. The purpose is to explore the complex relationship between performances, processing, microstructure and environmental degradation of AM materials and structures in various environments. Papers presented in this session qualify for submission to Special Issue of the Journal of Marine Science and Engineering (open access, CC journal, IF: 2.744, ranked as Q1 in WoS JCR category Marine Engineering) entitled “Degradation and Damage of Composite Materials in Marine Environment”: https://www.mdpi.com/journal/jmse/special_issues/YY1H472UL0. Authors will benefit from 20% off article processing charge.