I’ve never had luck shelling in Key West. The beaches are not what people think in the Keys (they are crushed coral so the ‘sand’ feels like rough like cat litter). Most seashells break up over the reef before making it to shore, although there are definitely exceptions. To shell in the Keys, you really need to get in the water and snorkel.
Anyhow, I was staying at the Sunset Key Cottages and went for a beach walk on their private beach each evening. I found my first keeper – a green sea urchin (empty of course). Kinda cool! I love its color and it actually made it home with me, unbroken.
If you’re looking for luxury accommodations in Key West, Sunset Key Cottages are fantastic. It’s a private island right off Mallory Square and the only way you can get there is by ferry, but you must be staying there or dining at their restaurant. Worth it.