Circle Layer

You can add circle areas to maps by making them out of a center coordinate and radius using CircleLayer and CircleMarkers.

CircleLayer class - flutter_map library - Dart API

CircleMarker class - flutter_map library - Dart API

An example CircleMarker

CircleLayer(
  circles: [
    CircleMarker(
      point: LatLng(51.50739215592943, -0.127709825533512),
      radius: 10000,
      useRadiusInMeter: true,
    ),
  ],
),

Excessive use of circles may create performance issues.