St. Lucie Inlet, Florida, Natural inlet in Martin County, Florida.

St. Lucie Inlet is a dredged channel between Hutchinson Island and Jupiter Island in Martin County, Florida, connecting the Atlantic Ocean to the Indian River Lagoon. It lies south of Bathtub Beach Reef, a sabellariid worm reef, and north of St. Lucie Inlet State Park, which has hard and soft coral reefs.

The inlet has been kept open by dredging for about 150 years. In 1844 Samuel Peck and settlers of the Indian River Armed Occupation Colony made the first recorded opening with picks and shovels. A dredge deepened it in 1892 for $2,000, and a 1981 project cost $8 million. Federal authorization under Section 201 of the Flood Control Act of 1965 set a channel 16 ft deep and 300 ft wide.

The inlet's name recalls the "Santa Lucia" shown on maps from 1500 and 1683, though scholars discount those early charts. The pirate Don Pedro Gilbert used the nearby natural inlet Gilbert's Bar as an escape route from deep-draft pursuit vessels. Today the channel is maintained by dredging, and sand pumped from it replenishes beaches south to the Martin–Palm Beach county line.

Access is easiest at high tide since this natural channel fluctuates with water levels. Boaters should stick to marked channels and use caution during rough conditions.

The beaches along Hutchinson Island, just north and south of the inlet, rank third in the Western Hemisphere for loggerhead sea turtle nesting. The inlet itself separates Hutchinson Island from Jupiter Island in Martin County.