We keep our ID cards, the golf cart keys, and my cell phone in a little zippered pouch that we leave with our towels, etc. on the chair/chaise lounge at poolside. It also helps me remember to take my phone out of my pocket and put it in that pouch
PRIOR to getting in the pool........been there, done that! Big 'duh' on my part.
The pouch could be stuffed into a shoe or wrapped up in a towel or whatever to keep it out of view.
Bill