Laminar flow surfaces with selected roughness distributions, and associated methods are disclosed. A representative method for designing an airfoil includes selecting a parameter that includes a flow behavior distribution and/or a surface shape for an airflow surface. Based at least in part on the selected parameter, the method can include (a) selecting a target roughness value and determining a chordwise location forward of which surface roughness is at or below the target roughness value and/or (b) selecting a target chordwise location and determining a roughness value for a region forward of the chordwise location, with the surface roughness at or below the roughness value. In particular embodiments, a percentage of a local chord length of the airfoil over which the roughness is below a target value decreases in a spanwise direction. In another embodiment, the roughness at a particular spanwise location can increase over at least three values, continuously, in a step manner, or otherwise.