Natural water edges are harder than pools because shorelines can be soft, irregular, muddy, and seasonally variable. A robot mower should have more margin than it would beside a stable hardscape edge.
The practical answer
Mud and soft banks reduce traction at exactly the point where a navigation error matters most. Keep virtual boundaries back from unstable soil and use a physical edge or landscaping transition where possible.
The constraint that matters most
Water levels and shoreline vegetation can change through the season, so a map that was safe in spring may not reflect summer erosion or saturated ground after storms.
How to set the mower up for it
Inspect the shoreline periodically, widen setbacks after heavy rain, and avoid routing the mower along narrow banks between water and another obstacle.
How we research robot mowers
We normalize manufacturer specifications around the buying constraints that actually change the decision: recommended mowing area, navigation architecture, slope capability, cutting-height range, obstacle sensing, charging behavior, multi-zone support, warranty, parts availability, and current pricing. We give more weight to property fit than to feature count.
Prices, specifications, firmware, and configuration-driven features can change. Check the current manufacturer page and local requirements before buying or installing equipment.