If you’ve ever hiked on the beach, you’ve felt the sand give way with every step you take. When you hike on wet sand that is packed, the going is much easier than on dry, soft sand.
The best area to hike is just above the water-line where footprints are quickly washed away by wave action. The benefit of this zone is that the sand will be compacted and any footprints you leave will be washed away quicker, leaving less of a trace and impact on the environment.
When the sand is piled and you are hiking up or across it, every step sinks or slips back making the going slow and more dangerous. Your the footprints can remain for days until either the wind slowly moves the sand around, it rains or large waves jump further ashore. Risks of stumbling, twisting your ankle, or causing a sand-slide increase as the slope gets steeper and you become more tired.
So, stick to the water-line, go slow and carefully place each step.