Having an argument. If the sandals are wet (which I think we can assume they are), then they have broken the surface, correct? And if they’ve broken the surface, then that leaves only buoyancy to hold them up.
I reason that they appear to be floating “on” the water because they are incredibly light, foam sandals, and only need to displace a very small amount of water to float.
The angle from which the photo was taken also hides any under-the-surface view of the sandals.
So, is it buoyancy or surface tension? Or both? Or neither? (A higher power?)