Blue waterproof phone pouch with yellow lanyard

I was wandering along the Florida Keys waterfront in Key West yesterday around 3pm, near Mallory Square and the ferry dock, when my blue waterproof phone pouch slipped from my pocket. It’s a 6x4 inch AquaGuard case with a bright yellow lanyard that makes it easy to spot in the sun, and there’s a small white sticker on the back reading 'Key West 305.' The pouch is a bit scratched along the bottom edge from deck steps, but the zipper still works. Inside is my unlocked iPhone and a couple of faded travel receipts; it’s sentimental—my sister gave me this on our last trip—and I’d really appreciate getting it back.