The ability of MLPs to accurately describe chemical processes in explicit solvents is critical for extending their application to more challenging systems. To this end, we investigated the solvent effects on the DA reaction between CP and MVK in explicitly modelled water and methanol. While this reaction exhibits only minor solvent effects compared to charged systems, several reports have shown rate acceleration and selectivity enhancement when water or aqueous solvent mixtures are employed. The reaction is accelerated up to 58-fold in water compared to methanol, and the endo/exo selectivity is enhanced by 8-fold in water over benzene. This behaviour is widely explained by the formation of stronger HBs between solvent and substrate at the TS compared to the reactants state (RS) and product state (PS). In addition, solvent polarity and hydrophobic effects have also been suggested to contribute to this enhancement. We trained four ACE MLPs for each endo/exo DA reaction between CP and MVK in either explicit water or methanol. For comparison, we also trained the models in implicit solvent, neglecting the presence of the explicit solvent molecules. Here, we describe the strategy employed to obtain the ACE MLP for the endo reaction in explicit water. A similar approach was used for the other systems (SI § S6 for further details). For the reaction in explicit solvents, the training set consisted of four subsets, each aimed at describing different types of interactions in the system. Subset 1 corresponds to the substrate complex (CP + MVK) and provides information about intramolecular interactions and intrinsic reactivity (Fig. ). Subsets 2 and 3 consist of the substrate with 2 and 33 water molecules, respectively, and aim at describing various solute-solvent interactions. Finally, subset 4 contains only water molecules, providing information about solvent-solvent interactions in bulk solvent. All subsets were generated independently using the AL scheme initiated from the transition state structure, except the pure water subset, which started from a random water configuration.