The invention relates to an EGR system, including a duct (48) with an inlet port (50) and an outlet port (56), which duct (48) includes a first duct section (54) with a first cross-sectional area (Al), a second duct section (56) with a second cross-sectional area (A2) and a transitional section (58) arranged between the first and second duct sections (54, 56). The transitional section (58) is designed so that a first virtual wall (60) is formed by EGR gases (25) in the transitional section (58) when the EGR gases (25) flow in the direction from the inlet port (50) to the outlet port (52) and a second virtual (74) wall is formed by a return flow (72) in the first duct section (54) when the return flow (72) flows from the outlet port (52) to the inlet port (50). The invention also relates to a combustion engine (2) with such an EGR system (4) and a vehicle (1) which includes such a combustion engine (2).