Quick Test:

Initially cut off about a 1.5 inch segment of paracord and dropped into a bowl of water. It floats, but just barely. It is very close to being neutrally buoyant.

It was still floating after about an hour.

I picked the cord up and compressed a small section -- the compressed part quit floating.

I then compressed the entire length of cord, and the cord sunk.

As a guess, trapped air in the weave caused the cord to float. This segment was from unused cord. I wouldn't depend on used paracord floating. It might float, but the entrained air may be squeezed out during use or the outside sheath damaged enough to allow the entrained air to escape.

As any engineering accurate answer to will paracord float -- maybe!

-Tommy