K Kilo · Line 3: Seasons & Beaches
Signal notes
- State researchers found that white sharks off Cape Cod spend almost half their time in water less than 15 feet deep.
- A purple flag at a National Seashore beach means a shark has been sighted.
- If caught in a rip current, swim parallel to the shore, then toward it; if you cannot, float or tread water and signal for help.
The Outer Cape’s ocean beaches are some of the most beautiful in New England, and they come with two hazards that people from calmer coasts often underestimate. One is the white shark, seen more often as the gray seal population has grown. The other is the rip current, which the National Weather Service warns can form even on calm, sunny days. Neither is a reason to skip the beach. Both are reasons to swim differently here.
Why the sharks are here
The Massachusetts Division of Marine Fisheries has studied white sharks off Cape Cod since 2009. It says seasonal sightings off the coast have increased, and that the Outer Cape draws them because of its growing population of gray seals, their main prey. The division has tagged more than 120 white sharks off the eastern coast of Cape Cod alone, and staff have tagged more than 230 overall. Many tagged sharks return to the Cape every year; when they leave in late fall they migrate to the southeastern United States and the Gulf of Mexico, and larger ones head into the open Atlantic.
The division describes the Cape Cod aggregation as one of only a handful of white shark hotspots in the world and unique on the US East Coast.
The finding that matters most to swimmers
In a study by state and Atlantic White Shark Conservancy researchers, white sharks off Cape Cod spent almost half their time in water less than 15 feet deep, which the division notes is exactly where they can overlap with people. The National Park Service adds that sharks hunt seals in shallow water. Calm, knee-to-chest-deep water is not automatically out of their range.
Bites remain rare. Both agencies point to the same turning point: a fatal attack on a boogie boarder off Wellfleet in September 2018.
Shark Smart: the Park Service rules
The Cape Cod National Seashore, local towns, the state shark program and the conservancy run a joint Shark Smart campaign. Its advice is short:
- Stay close to shore, where rescuers can reach you.
- Do not isolate yourself. Swim, paddle, kayak and surf in groups.
- Avoid areas where seals are present or where schools of fish are visible.
- Avoid murky or low-visibility water.
- Limit splashing.
- Follow all signs, flags and lifeguard instructions.
Look for the purple shark flag. At Seashore beaches it indicates that a shark has been sighted. On a lifeguarded beach, a sighting means the water is temporarily closed to swimming and surfing until guards say it is safe to go back in.
Fall is the riskiest combination
The timing works against late-season visitors. Lifeguards at the six Seashore beaches are on duty only from late June through Labor Day, but the park says shark activity remains high through September and October, and spotter planes regularly report sharks near the Outer Cape, including in areas used by swimmers. In other words, the quiet weeks after Labor Day are also the weeks with no one watching the water. If you swim then, stay in shallow water, stay near others and skip it entirely when seals are close by. More on the season is in The Best Time to Visit Cape Cod: Air and Water Temperatures, Lifeguards and Prices by Month.
How the warnings reach the beach
Shark warnings are built into the regular beach safety system. Massachusetts public health rules allow a beach to be posted not only for bacteria but for safety hazards, and the Department of Public Health lists sharks among them, alongside fast currents, sharp drop-offs and poor visibility.
Technology helps too. The state division expanded its network to more than 200 acoustic receivers in coastal waters and placed real-time receivers off popular Outer Cape beaches, including Newcomb Hollow and LeCount Hollow in Wellfleet, Head of the Meadow in Truro, Nauset Beach in Orleans and North Beach in Chatham. Those send alerts to beach managers and lifeguards when a tagged shark comes close. Visitors can follow sightings and report their own on the free Sharktivity app, which the Park Service recommends.
Rip currents: the more common danger
The Park Service lists rip tides, shore break and strong undertows as hazards at Seashore beaches. The National Weather Service adds a point that surprises many people: rip currents often form on calm, sunny days, so good beach weather does not mean safe swimming. It advises checking the local beach forecast before you go and swimming at beaches with lifeguards.
If a rip current catches you
| Step | What to do |
|---|---|
| 1 | Stay calm to save energy and think clearly |
| 2 | Do not fight the current. Swim out of it parallel to the shoreline |
| 3 | Once out of the current, swim toward shore |
| 4 | If you cannot swim out, float or tread water calmly |
| 5 | If you cannot reach shore, wave your arms and yell for help |
If you see someone else in trouble, get a lifeguard. If none is on duty, call 911. Every Seashore beach except Nauset Light has an emergency call box that connects directly to emergency services, and the park keeps bleeding-control kits at its beaches.
Other ways the sea surprises people
- Never turn your back to the ocean; shore break can knock over adults in shallow water.
- Do not dig holes deeper than knee level or climb dunes and bluffs. The park warns that sand collapses easily.
- Swimmer’s itch has been reported at Salt Pond in Eastham.
Tip: Wherever you swim, read the signs and flags at the entrance before you go in. The Park Service’s own advice is to read and heed the advisories posted at each beach. For the Seashore’s six staffed beaches, see Cape Cod National Seashore Beaches: The Six Lifeguarded Beaches, Fees, Passes and Pet Rules.