Dietary crude protein (CP) reduction is a strategy mostly implemented in Europe to improve nitrogen (N) efficiency, protein autonomy and environmental performance. This study aimed to explore the potential of CP reduction to reduce the environmental impacts of pig production in three contrasted contexts (Brazil, Canada, and France), characterized by raw materials used and pig farming practices. For each country, control treatments were formulated in 6 economic contexts to represent current practices and minimum CP reachable was determined. Least cost formulation was used in the six economic contexts to formulate a very low CP diet with a CP level 5 g/kg above minimum CP and an intermediate CP level. Pig performance was simulated with an individual-based model of the pig-fattening unit including InraPorc, and farm gate LCA was performed for all diets. Control CP levels were higher in Canada and Brazil than in France and CP reduction was greater (P < 0.001). Dietary CP reduction increased cereal and free amino acid inclusion in all contexts (P < 0.001), soybean meal inclusion decreased more with CP reduction in the French context (P < 0.001), co-products inclusion increased in Brazilian contexts but decreased in French and Canadian ones (P < 0.001). Growth performance was not affected by CP reduction (P < 0.001). N efficiency was improved in all contexts (P < 0.001), but to a lower extent for the French context, due to higher N efficiency in the control (P < 0.001). Acidification was reduced with CP in all contexts, with larger reductions in Canada and Brazil (P < 0.001). Climate change was only reduced in the French context and increased in other contexts (P < 0.001). Other evaluated impacts were stable or increased (P < 0.001). While acidification is reduced by CP reduction regardless of context, mitigation of other impacts depends on feedstuffs used and especially impact of corn compared to soybean meal in the production context.