Marine geophysical surveys with distributed seismic sources. At least some of the example embodiments are methods including performing a marine geophysical survey by: towing a plurality of high-frequency sources spread along a width of an array of sensors, the high-frequency sources having a first source density with respect to the width; and towing a plurality of mid-frequency sources spread along the width, the mid-frequency sources have a second source density with respect to the width, the second source density lower than the first source density; and towing a low-frequency source along the width; activating the high-frequency, mid-frequency, and low-frequency sources.