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Spectacular Shelling at Cayo Costa State Park

There's shelling and then there's Cayo Costa shelling. This State Park in the gulf coast of Florida is one not to be missed, perfect spot for nature treasure hunting.

Nature Treasure Hunter - A rewarding shelling expedition to Cayo Costa State Park.  Along with this huge lightning welk, Isla Nature Treasure Hunter collected a wide variety of shells and even saw a ghost crab.
Cayo Costa State Park Lightning Whelk


Cayo Costa State Park is one of the largest barrier island in Florida with 9 miles of unspoiled beach only accessible by boat.

“It is located along the Gulf of Mexico and is considered one of the best shelling beaches in the world.”

The island has no developments so it has retained its natural beauty and unique vegetation as when it was discovered 500 years ago.


The island is only accessible by charter boat, private boat, ferry or helicopter. We joined Captiva Cruise‘s half day tour at McCarthy’s Marina. The ferry ride was about half an hour with dolphin watching along the way and was dropped off at the south end of the island with two hours of shelling time. If you prefer a longer stay, they also offer a full day tour with 4 hours on the north end of the island where the trails and amenities are located.

The trip was absolutely worth it. In the short two hours we were there, we found a variety of seashells we did not see in Captiva or Sanibel. We even came across a Ghost Crab who seemed a bit dried out in the sun.


Here is a list of shells we found during our shelling expedition.

Sand Dollars

Nature Treasure Hunter - Cayo Costa Sand dollar
Sand Dollar Cayo Costa

Live sand dollars are brown and hairy so only pick the dead ones that are white. The best place to look for perfect sand dollars here are actually in the shallow water. They are often slight buried into the sand so wade through knee high water and keep a close watch for anything slight flat.

Lightening Whelk Shells

Nature Treasure Hunter - Lightening Whelk Cayo Costa
Lightening Whelk Cayo Costa

Lightening whelk have counterclockwise shell spiral and can grow to 16 inches. We found a lot of mid size shells but the big one we found was still alive so we put it back in the water.

Fighting Conch

Nature Treasure Hunter - Fighting Conch Cayo Costa
Fighting Conch Cayo Costa

Fighting conch can be around 3 - 4 inches. We found fighting conch in Captiva as well but we had to dive for the big ones. Here there were an abundance of the large ones on the sandy beach ready for the picking.

Guady Nautica

Nature Treasure Hunter - Guady Nautica Cayo Costa
Guady Nautica Cayo Costa

Guady Nautica is a type of moon snail with an interesting pattern.

Atlantic Giant Cockle

Nature Treasure Hunter - Atlantic Giant Cockle Cayo Costa
Atlantic Giant Cockle Cayo Costa

A true cockle shell has a rounded, heart-shaped shell with a slightly ribbed texture. We found quite a few large ones in Cayo Costa and they were all in tac.

Tulip Banded Shell

Nature Treasure Hunter - Tulip Banded Shell Cayo Costa
Tulip Banded Shell Cayo Costa

Seldom over 4" long, the Tulip Banded Shell is distinctive with the 7 brown lines. We didn't find any in Captiva or Sanibel but we were lucky enough to find this one here.

Lettered Olive

Nature Treasure Hunter - Lettered Olive Shell
Lettered Olive Shell

Olive shells has extremely glossy shell and were everywhere in all different sizes.

Calico Scallop

Nature Treasure Hunter - Calico Scallop Shell Cayo Costa
Calico Scallop Shell Cayo Costa

Calico scallops are almost like bay scallops but they have the patch work of red and pink on the top half.

Sunray Venus

Nature Treasure Hunter - Sunray Venus Cayo Costa
Sunray Venus Cayo Costa

Sunray Venus is named for the distinctive pattern reminiscent of the rays of the setting sun and is the largest venus shell.

Kitten’s Paw

Nature Treasure Hunter - Kitten's Paw Cayo Costa
Kitten's Paw Cayo Costa

Named as Kitten's Paw by most collectors because of the resemblance, they are about an inch long.


Nature Treasure Hunter - Ceriths Cayo Costa
Ceriths in Cayo Costa

The slender Cerith shells we found were quite small, no bigger then 15mm.


Nature Treasure Hunter - Auger in Cayo Costa
Auger in Cayo Costa

The Auger is a long narrow tapered shell that can grow up to 1 3/4".

Cut Ribbed Ark

Nature Treasure Hunter - Cut Ribbed Ark Cayo Costa
Cut Ribbed Ark Cayo Costa

Cut ribbed ark can grow to 4 1/2" and have 30-38 grooved radial ribs and concentric ridges between the ribs

Worm snail

Nature Treasure Hunter - Worm Snail in Cayo Costa
Worm Snail Cayo Costa

Worm snails are irregular tubular spiral shells. We found only a broken piece.

Florida Spiny Jewelbox

Nature Treasure Hunter - Florida Spiny Jewelbox Cayo Costa
Florida Spiny Jewelbox Cayo Costa

Florida spiny jewelbox doesn’t get larger the 1 1/2" in length and have prickly spines on the shell

Scotch Bonnet

Nature Treasure Hunter - Scotch Bonnet Cayo Costa
Scotch Bonnet Cayo Costa

Scotch bonnet is the offical shell of North Carolina. It has small orange/brown squares that give it a plaid appearance.

Calico Clam

Nature Treasure Hunter - Calico Clam Cayo Costa
Calico Clam Cayo Costa

The calico clam shells has an exterior of creamy white with a checkerboard pattern of brownish red and they are not very big.

Stiff Pen Shell

Nature Treasure Hunter - Stiff Pen Shell Cayo Costa
Stiff Pen shell Cayo Costa

Stiff pen shell can grow up to 12" long and can produce black pearls.

The perfect time for shelling is after a storm. The rough waters and storm usually wash up amazing nature treasures. If you live close to Cayo Costa, make sure you schedule in a trip.






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