Seal Watching: Where & When to See Seals

Gray Seals vs. Harbor Seals

Two seal species inhabit Nantucket's waters, and learning to distinguish between them adds richness to any seal-watching outing. Both species are protected under the Marine Mammal Protection Act, and both have thrived since hunting and bounty programs ended in the 1970s.

Gray Seals (Halichoerus grypus)

Gray seals are the dominant species around Nantucket and the stars of most seal-watching excursions. Males are enormous - up to 8 feet long and weighing as much as 800 pounds. Females are considerably smaller, typically around 6 feet and 350 pounds. You'll recognize gray seals by their distinctive "horse head" profile - a long, straight snout that gives them a noble, almost Roman appearance. Their scientific name, Halichoerus grypus, translates to "hook-nosed sea pig," though that seems a bit unkind to such elegant animals.

Gray seals are present around Nantucket year-round, but their numbers peak dramatically from December through April. During this period, they haul out on sandbars and remote beaches in impressive congregations. Pupping season runs from late December through February, when mothers give birth to white-coated pups that shed their natal fur after about three weeks.

Harbor Seals (Phoca vitulina)

Harbor seals are the smaller, friendlier-looking cousins of gray seals. They typically measure 5-6 feet long and weigh 150-300 pounds. Their most distinguishing feature is a rounded, dog-like face with a concave forehead - quite different from the gray seal's elongated profile. Harbor seals tend to be more cautious around humans and boats, though they're equally curious when they feel safe.

Harbor seal numbers around Nantucket peak in spring and fall, when they're migrating through the area. Unlike gray seals, harbor seals don't breed in significant numbers locally - they prefer calmer, more protected waters for pupping. But during migration seasons, you'll often see them mixed in with gray seal groups or hauled out on their own on smaller sandbars.

Telling Them Apart

From a distance, size is your best clue - gray seals are noticeably larger. Up closer, look at the head shape: gray seals have that long, straight snout, while harbor seals have a rounder, more dog-like face with a dip at the forehead. Coloring varies widely in both species, so don't rely on that alone. When you see a truly massive seal lounging on a sandbar, you're almost certainly looking at a male gray seal.

The Seal Population Comeback

The abundance of seals around Nantucket today represents one of New England's great conservation success stories - though it's a story with complications. Understanding this history adds context to what you'll see.

For most of the 19th and 20th centuries, seals in New England were actively persecuted. Massachusetts paid bounties on seal kills from 1888 until 1962, viewing them as competitors for commercially valuable fish. By the mid-20th century, gray seals had been essentially eliminated from southern New England waters, with only small remnant populations surviving in Maine and Canada.

Everything changed with the Marine Mammal Protection Act of 1972, which prohibited the killing and harassment of all marine mammals in U.S. waters. Protected from hunting, seal populations began to recover. The rebound has been nothing short of spectacular. Muskeget Island, the small island west of Nantucket, went from hosting a handful of seals in the 1990s to becoming the largest gray seal breeding colony in the eastern United States, with an estimated 4,000-5,000 pups born there each winter.

This recovery isn't universally celebrated. Commercial fishermen report significant losses to seals, and the population growth has been linked to an increase in great white shark sightings in Cape Cod waters - seals being the sharks' preferred prey. But for wildlife watchers, the return of seals has transformed Nantucket into a premier destination for marine mammal viewing.

Best Seal Watching Locations

Seals can appear almost anywhere around Nantucket - including right in the harbor - but certain locations offer much more reliable viewing opportunities.

Great Point

Access: 4WD vehicle with permit, guided tour, or 5+ mile hike
Best time: Year-round, peak December-April

The sandbars and shoals surrounding Great Point Lighthouse host the most accessible seal haul-outs on Nantucket proper. Where Nantucket Sound meets the Atlantic Ocean, shifting sands create ideal conditions - abundant fish, protected shallows, and relative isolation from human activity. On a good day during peak season, you might count 50 or more seals lounging on exposed bars.

If you're driving out with a 4WD permit, arrive at low tide when sandbars are most exposed. Bring binoculars and scan carefully - seals blend into their surroundings better than you'd expect. The lighthouse itself makes an excellent landmark. Seals often haul out within sight of it, though the specific bars they favor shift with sand movement and tides.

Muskeget Island

Access: Boat tour only
Best time: December-February for pupping season

Muskeget is where seal watching on Nantucket becomes truly extraordinary. This uninhabited island, about 7 miles west of Nantucket, hosts the largest gray seal breeding colony in the eastern United States. During pupping season, thousands of seals - literally thousands - gather on the beaches and sandbars. Mothers nurse pups, males compete for mating opportunities, and the air fills with the otherworldly sounds of seal vocalizations.

You cannot land on Muskeget (it's closed to protect the seals), but specialty charter boats circle the island at respectful distances, providing views that will stay with you forever. Weather conditions must cooperate - the trip crosses exposed open water - so trips are weather-dependent and often cancelled. But if you have a few winter days on Nantucket and conditions align, a Muskeget seal tour is absolutely worth the investment.

Coatue

Access: Boat, kayak, or 4WD
Best time: Year-round

The long barrier beach of Coatue curves northward toward Great Point, creating a protected inner harbor and excellent seal habitat along its outer edges. Seals frequently fish in these waters and haul out on smaller sandbars, particularly near the tip of Coatue. If you're kayaking from town toward the point (an ambitious but rewarding paddle), keep your eyes on the water - you may have curious company.

Tuckernuck and Monomoy

Access: Boat tour
Best time: Winter months

While technically outside Nantucket proper, the waters around Tuckernuck Island (just west of Nantucket) and the Monomoy National Wildlife Refuge (off Chatham on Cape Cod) host significant seal populations. Some Nantucket charter operators will arrange trips to these areas, particularly when Muskeget conditions aren't favorable. Monomoy's seal population rivals Muskeget's, and the refuge offers excellent viewing opportunities.

Nantucket Harbor

Access: Waterfront areas - no special access needed
Best time: Year-round, opportunistic

Don't overlook the harbor. Seals regularly swim into Nantucket Harbor following fish, and sightings from the wharves, Children's Beach, or Brant Point are more common than most visitors realize. Harbor sightings are unpredictable - you might see several seals in an hour or none in a week - but keep your eyes on the water during any waterfront time. That dark shape bobbing in the distance might reward a second look.

Seasonal Timing: When to See Seals

While seals can be spotted around Nantucket in any month, timing dramatically affects your chances and the quality of your experience.

Peak Season: December through April

Winter and early spring offer the best seal watching on Nantucket - by a significant margin. This is when both species concentrate in local waters, when haul-out numbers peak, and when the spectacular Muskeget pupping season occurs. If seal watching is a priority for your trip, consider a winter visit.

January and February represent the absolute peak. Muskeget will have thousands of seals; Great Point haul-outs will be at their largest; and even casual harbor sightings become more common. The tradeoff, of course, is that winter weather on Nantucket can be harsh, and boat tours are more likely to be cancelled due to conditions.

Shoulder Seasons: May-June and October-November

Spring and fall offer a middle ground. Seal numbers are lower than winter peaks, but viewing is still very much possible, and weather conditions are generally more pleasant for boat excursions. Harbor seals are particularly likely during their spring and fall migrations. These months can be excellent for combining seal watching with other activities in comfortable conditions.

Summer: June through August

Summer seal watching is possible but less reliable. Seals disperse more widely in warmer months, and the large haul-out aggregations characteristic of winter don't form. You may still spot individual seals in the harbor or around Great Point, but dedicated seal-watching trips typically don't run in summer. If seals are your main focus, save them for another season; if you're hoping for a bonus sighting during a summer beach vacation, keep your eyes open but don't count on it.

Best Time of Day

Seals are active throughout the day, but certain times offer advantages. Early morning often finds more seals hauled out, as they've spent the night resting on sandbars. Boat tours in the morning also benefit from typically calmer winds. Late afternoon works well too, with beautiful light for photography. Midday can be excellent for harbor sightings when seals follow fish actively feeding.

Tides matter more than time of day for land-based viewing. Low tide exposes the sandbars where seals haul out. Check tide tables and plan your Great Point or Coatue visits around low tide for the best views.

Seal Watching Boat Tours

While land-based viewing is rewarding, the most memorable seal experiences come from the water. Boat tours get you closer (within safe, legal distances) and reach locations inaccessible from shore.

What to Expect

A typical seal-watching tour runs 2-3 hours. Boats head to known haul-out locations - often Great Point, the outer sandbars, or Muskeget - and cruise slowly at respectful distances. Captains know where seals congregate and how to position boats for optimal viewing without causing disturbance.

Seals are naturally curious. While boats maintain appropriate distances from hauled-out seals, swimming seals often approach on their own initiative. These voluntary close encounters - a seal surfacing nearby to check out the boat and its passengers - are among the most thrilling wildlife experiences Nantucket offers.

Most winter tours focus on Muskeget when weather permits, shifting to Great Point and closer waters when conditions don't allow the longer crossing. Be flexible with your expectations - weather drives everything, and captains prioritize safety.

Preparing for Your Tour

Winter seal watching requires serious preparation for cold. Conditions on the water feel dramatically colder than on land. Dress in warm, windproof layers: thermal underwear, fleece or wool mid-layers, and a waterproof outer shell. Bring a warm hat that covers your ears, insulated gloves (fingerless gloves underneath allow camera operation), and thick socks. Operators may provide some shelter, but expect to spend time on deck for the best views.

If you're prone to seasickness, take precautions. Winter seas can be rough, and the motion affects even experienced boaters. Dramamine, ginger supplements, or prescription patches work for many people - start them before boarding. Sitting outside with fresh air and watching the horizon helps once underway.

Charter Options

• Shearwater Excursions - Dedicated wildlife tours with naturalist guides who provide excellent interpretation
• Nantucket Island Tours - Combination seal and lighthouse trips that cover multiple interests
• Private fishing charters - Many captains will customize trips for wildlife viewing; ask around at the boat basin

Book in advance, especially for Muskeget trips during peak season. Weather cancellations are common - build flexibility into your schedule if possible. Most operators require minimum group sizes for winter trips, so solo travelers may need to join existing departures.

Land-Based Viewing Spots

You don't need a boat to see seals on Nantucket. Several land-accessible locations offer viewing opportunities, though you'll want binoculars or a spotting scope for the best experience.

Great Point (by 4WD or hike)

The remote tip of Nantucket requires either a 4WD vehicle with an oversand permit or a long hike (5+ miles each way from the end of Wauwinet Road). Either way, you're rewarded with access to the best land-based seal viewing on the island. From the beach near the lighthouse, scan the surrounding waters and sandbars with binoculars. At low tide during peak season, multiple haul-out sites should be visible.

Brant Point

The short walk to Brant Point Lighthouse puts you at the harbor mouth, where seals occasionally swim past. This isn't a dedicated seal-watching spot, but it's easily accessible and worth watching during any visit. Bring binoculars and scan the water - you might get lucky.

Jetties Beach

The north shore jetties offer a vantage point over waters that seals traverse. Again, dedicated viewing isn't reliable here, but opportunistic sightings happen, particularly in winter and early spring.

Tips for Land-Based Viewing

• Bring binoculars - seals maintain distance from shore
• Time visits to low tide when sandbars are exposed
• Scan systematically rather than glancing around
• Watch for heads popping up in the water, not just hauled-out seals
• Be patient - seals come and go

Viewing Distance and Safety

Responsible seal watching prioritizes the animals' welfare. Both for their protection and your safety, maintaining appropriate distance is essential.

Legal Requirements

The Marine Mammal Protection Act prohibits harassing, pursuing, or disturbing marine mammals. Federal guidelines recommend staying at least 150 feet (50 yards) from hauled-out seals. While there's no specific legal distance for seals in the water, the principle remains: don't pursue or crowd them.

Why Distance Matters

When seals that have hauled out are approached too closely, they flee into the water. This might seem like a minor inconvenience, but repeated disturbances have serious consequences. Hauled-out seals are resting and thermoregulating - activities essential to their health. Mothers with pups may abandon their young if repeatedly flushed. Even without such dramatic outcomes, chronic disturbance causes stress that affects feeding, reproduction, and overall fitness.

The best seal encounters happen on the animals' terms. Keep your distance, use binoculars or telephoto lenses, and let curious seals approach you if they choose. Those voluntary close encounters - a seal swimming up to investigate your boat - are the most magical precisely because they're the seal's decision.

Safety Considerations

Seals look cute but can bite if they feel threatened. Never attempt to touch, feed, or corner a seal. On land, a seal can move faster than you might expect over short distances. In the water, they're in their element and you're the clumsy one. Give them space, and enjoy watching from a distance.

If you encounter a seal pup alone on a beach, leave it alone. Mother seals regularly leave pups for hours while foraging. The pup isn't abandoned - it's waiting. Well-meaning "rescues" of healthy pups cause more harm than good. If you genuinely believe a seal is injured or in distress, contact the International Fund for Animal Welfare's stranding hotline: (508) 743-9548.

Photography Tips

Seal watching offers outstanding photography opportunities, but the conditions require preparation and appropriate equipment.

Essential Gear

• Telephoto lens: 200-400mm minimum. Seals are distant, and a long lens is essential for filling the frame without approaching too closely.
• Fast shutter speeds: Boats move, seals move, and light can be challenging. Shoot at 1/500 or faster when possible.
• Weather protection: Salt spray is murder on cameras. Bring a rain cover or at least a plastic bag you can drape over your gear.
• Extra batteries: Cold weather drains batteries rapidly. Keep spares warm in an inside pocket.
• Lens cleaning supplies: Salt spray on your front element is inevitable. Bring a microfiber cloth.

Shooting Techniques

• Burst mode: Seal behavior is unpredictable. Shoot bursts to capture the perfect moment when a seal lifts its head or makes eye contact.
• Eye contact: Photos where the seal appears to look at the camera connect with viewers. Wait for those moments.
• Golden hour light: Early morning and late afternoon provide warm, flattering light that transforms seal portraits.
• Include environment: Seals against sandbars, lighthouse, ocean - context tells a story beyond a tight portrait.
• Be ready: The best moments happen fast. Keep your camera ready and your settings dialed in.

Smartphone Tips

Phone cameras struggle with distant wildlife, but you can still get memorable shots. Use any digital zoom sparingly (it degrades quality), focus on closer seals that approach the boat, and consider video for capturing seal behavior even when photo quality is limited.

What to Bring

For Boat Tours

• Multiple warm layers (more than you think you'll need)
• Windproof and waterproof outer layer
• Warm hat covering ears
• Gloves (consider fingerless for camera operation)
• Binoculars
• Camera with telephoto lens
• Seasickness remedy if needed
• Water and snacks
• Sunglasses (water reflection is intense)
• Sunscreen (yes, even in winter)

For Land-Based Viewing

• Binoculars or spotting scope
• Camera with telephoto lens
• Layered clothing appropriate to season
• Water and snacks
• Patience