My leather leashes are in the water frequently and have never had a problem. I would think a leather collar would be fine.
With that, you might try a martingale style collar. You can have it looser on her neck because it will tighten some when the leash goes taut. Mine are sized to slide over the dog's head when loose, but not when pulled taut. When pulled taut it just fits snugly rather than choking.
With that, you might try a martingale style collar. You can have it looser on her neck because it will tighten some when the leash goes taut. Mine are sized to slide over the dog's head when loose, but not when pulled taut. When pulled taut it just fits snugly rather than choking.