A gas turbine engine component (60, 160, 260, 460) comprising: an external wall extending in a thickness direction between first and second wall surfaces, the first wall surface bounding an internal cavity (168, 268, 468), the external wall surface establishing an external surface contour (162SC, 362SC, 462SC) and at least one surface depression (174, 274, 474) along the external surface contour (162SC, 362SC, 462SC), the at least one surface depression (174, 274, 474) having concave geometry established by upstream (174-1, 274-1, 474-1) and downstream (174-2, 274-2, 474-2) arcuate faces sloping inwardly from opposed sides of a rim (176, 276, 476) along the external surface contour (162SC, 362SC, 462SC) to join at a valley (178, 278, 478), wherein the valley (178, 278, 478) is established at a maximum depth of the at least one surface depression (174, 274, 474) relative to the rim (176, 276, 476); wherein the external wall includes at least one cooling passage (166, 166', 266, 466) extending along a longitudinal axis between an inlet port (166A, 166A', 266A, 466A) and an outlet port (166B, 166B', 266B, 466B), the outlet port (166B, 166B', 266B, 466B) is established along the upstream face (174-1, 274-1, 474-1) of the at least one surface depression (174, 274, 474), and the at least one cooling passage (166, 166', 266, 466) is oriented such that a projection of the longitudinal axis has a component that extends in a direction towards the downstream face (174-2, 274-2, 474-2); wherein the at least one surface depression (174, 274, 474) expands outwardly from the valley (178, 278, 478) to establish a diffuser (180, 280, 480), and the at least one cooling passage (166, 166', 266, 466) interconnects the internal cavity (168, 268, 468) and the diffuser (180, 280, 480); and characterized in that the component is an airfoil, the airfoil includes an airfoil section extending in the chordwise direction between a leading edge (62LE, 162LE) and a trailing edge (62TE, 162TE), and the outlet port (166B, 166B', 266B, 466B) is situated along the at least one surface depression (174, 274, 474) between the valley (178, 278, 478) and the leading edge (62LE, 162LE) of the airfoil section with respect to the chordwise direction. an external wall extending in a thickness direction between first and second wall surfaces, the first wall surface bounding an internal cavity (168, 268, 468), the external wall surface establishing an external surface contour (162SC, 362SC, 462SC) and at least one surface depression (174, 274, 474) along the external surface contour (162SC, 362SC, 462SC), the at least one surface depression (174, 274, 474) having concave geometry established by upstream (174-1, 274-1, 474-1) and downstream (174-2, 274-2, 474-2) arcuate faces sloping inwardly from opposed sides of a rim (176, 276, 476) along the external surface contour (162SC, 362SC, 462SC) to join at a valley (178, 278, 478), wherein the valley (178, 278, 478) is established at a maximum depth of the at least one surface depression (174, 274, 474) relative to the rim (176, 276, 476); wherein the external wall includes at least one cooling passage (166, 166', 266, 466) extending along a longitudinal axis between an inlet port (166A, 166A', 266A, 466A) and an outlet port (166B, 166B', 266B, 466B), the outlet port (166B, 166B', 266B, 466B) is established along the upstream face (174-1, 274-1, 474-1) of the at least one surface depression (174, 274, 474), and the at least one cooling passage (166, 166', 266, 466) is oriented such that a projection of the longitudinal axis has a component that extends in a direction towards the downstream face (174-2, 274-2, 474-2); wherein the at least one surface depression (174, 274, 474) expands outwardly from the valley (178, 278, 478) to establish a diffuser (180, 280, 480), and the at least one cooling passage (166, 166', 266, 466) interconnects the internal cavity (168, 268, 468) and the diffuser (180, 280, 480); and characterized in that the component is an airfoil, the airfoil includes an airfoil section extending in the chordwise direction between a leading edge (62LE, 162LE) and a trailing edge (62TE, 162TE), and the outlet port (166B, 166B', 266B, 466B) is situated along the at least one surface depression (174, 274, 474) between the valley (178, 278, 478) and the leading edge (62LE, 162LE) of the airfoil section with respect to the chordwise direction.