Aliphatic polyketones are a rediscovered polymer family of highly polar thermoplastic engineering polymers of high crystallinity. Due to their chemical structure they show an interesting combination of materials behaviour. Mechanically loaded polyketones exhibit good modulus and strength values paired with high deformability and energy absorption. Polyketones show a low creep tendency, especially fibre-reinforced types, and good wear and friction properties. They feature an excellent chemical resistance, especially against hydrolysis and low moisture absorption with low swelling in water. Furthermore polyketones show good gas barrier properties. Due to the technical profile and the easy and energy efficient processing polyketones may be considered as interesting alternative materials for water as well as electronic and structural components. Regarding these possible application fields polyketones have to be analysed regarding the impacts of water absorption and elevated temperatures and have to be compared with polymeric materials actually used in these fields, e.g. Polyamide 12. Respecting wet environments at elevated temperatures a testing route was defined to evaluate the suitability of polyketones in wet environments compared to engineering polymers actually used in these applications. In this work the mechanical and thermo-mechanical behaviour of aliphatic polyketones compared to Polyamide 12 is investigated, considering the influence of water, temperature and a combination of both impacts, extending the knowledge of the behaviour of polyketones.