Nantucket Sound

Warm Water, Big Fish

Nantucket Sound is bounded by the south shore of Cape Cod to the north, Martha's Vineyard to the west, and the island of Nantucket to the east. The sound is relatively shallow — averaging 30 to 50 feet in most areas — and the sandy, shell-covered bottom warms quickly in summer, creating ideal habitat for baitfish, crustaceans, and the gamefish that feed on them. Fluke, sea bass, scup, and striped bass thrive in these protected waters from May through October.

East of Nantucket, the bottom drops off into the Nantucket Shoals — a vast expanse of shifting sand bars and shallow ridges that extend for miles into the open Atlantic. These shoals are legendary among Cape Cod fishermen for producing doormat fluke, the largest summer flounder caught anywhere on the East Coast. The combination of strong current, sandy bottom, and abundant sand eels creates conditions that grow flatfish to extraordinary size.

Beyond the shoals, the continental shelf drops toward deep water where bluefin tuna, sharks, and other pelagic species patrol during the warm months. Nantucket Sound serves as both a productive fishery in its own right and a gateway to these offshore grounds, making it one of the most strategically valuable bodies of water for Cape Cod charter fishing.

Best Times & Conditions

Nantucket Sound fishing peaks from June through September when water temperatures are warmest. The Nantucket Shoals fluke trip runs June 1 through August 31, when doormat-class flatfish are most concentrated on the shoals. Sea bass and scup fishing is reliable all summer. Striped bass move through the sound during the spring and fall migrations, with bluefish and bonito filling in during July and August. Calm conditions and moderate southwest winds are ideal for comfortable fishing across the sound's open water.