We have found that Marine Grade Reflective tape purchased at a Boat Shop works very well and is quite durable. I put strips of it on the bottom of our black rubber fins nearly two years ago. WE do a lot of shore dives where entering/exiting involves standing/climbing/walking across rocks and rubble and the tape has stood up very well. It is highly reflective so we can take off a fin and wave it at the boat or shine a torch (flashlight) on it to light it up.
We have not had to use them on the surface yet but have found them very helpful in locating buddies in poor viz. Most of our dive group have various patterns of the stuff on their fins now. Helps us to know who we are following and id each other at a distance. It also makes it easier to ID your fins in the pile on the boat. What I like about them is that they are always there as long as you are using your own fins. No thought no effort simple additional bit of signaling equipment.
We have not had to use them on the surface yet but have found them very helpful in locating buddies in poor viz. Most of our dive group have various patterns of the stuff on their fins now. Helps us to know who we are following and id each other at a distance. It also makes it easier to ID your fins in the pile on the boat. What I like about them is that they are always there as long as you are using your own fins. No thought no effort simple additional bit of signaling equipment.