What to Expect at Green Harbor

Green Harbor is a working harbor in Marshfield, on the South Shore between Plymouth and Boston, where you can fish for striped bass, flounder, and other bottom fish from the shore, jetties, and boats. The harbor sits at the mouth of the Green Harbor River and opens into Massachusetts Bay, so you get both tidal river access and open-water conditions depending on where you fish. The water is coldest in winter and warmest in late summer, which shifts what species are active and where they hold.

The harbor is also a shellfishing area — you can dig for soft-shell clams and quahogs if you hold a town permit. Access is straightforward: there is public parking, a boat launch, and several spots where you can walk out to fish without a boat. The harbor gets busy on weekends and during peak season, but it is not as crowded as some Boston-area spots, and the mix of river and bay water means conditions can be good even when nearby harbors are rough.

Key Takeaways

  • Striped bass run through Green Harbor in spring and fall, with summer and winter holding smaller numbers of resident fish and schoolies.
  • Flounder and other bottom fish are present year-round but most abundant from late spring through early fall.
  • You need a Massachusetts saltwater fishing license to fish, and a separate shellfishing permit from Marshfield if you want to dig clams or quahogs.
  • Public access includes parking at the harbor, a boat launch, and jetties and shore spots where you can fish without a boat.
  • Tides matter significantly here — slack water and the first two hours of incoming tide are usually most productive.

Seasons and What Fish Are Active

Spring (April through May) brings the first wave of striped bass as they move north from their winter grounds. Fish are typically 18 to 28 inches, though larger fish move through later in the season. The water is cold and clearing, so live bait and slow-moving lures work better than fast retrieves. Flounder start to show up in late April and May as the water warms.

Summer (June through August) is when the harbor is most crowded and most productive. Stripers are present but scattered — some fish stay in the deeper channels, while schoolies (smaller fish under 18 inches) patrol the shallows and jetties. Flounder are abundant and willing, especially around the deeper holes and channel edges. This is also peak shellfishing season if you have a permit.

Fall (September through November) brings another strong run of striped bass, often larger than spring fish. The water cools, baitfish move through, and fishing can be excellent from mid-September through October. By November, water temperature drops and fish become less active, though you can still catch them on the right tides.

Winter (December through March) is slow. Stripers are present but deep and lethargic. Some anglers fish for flounder and other bottom fish, but the harbor is quieter and colder. Access can be limited by ice or rough conditions, though the harbor rarely freezes solid.

How to Fish Green Harbor — Techniques and Locations

From shore and jetties, you can reach stripers and flounder with live bait (eels, mackerel, herring) or artificial lures. The jetties on the north and south sides of the harbor entrance are productive for stripers, especially on moving tides. Cast live eels or work topwater lures early and late in the day. For flounder, use live baitfish or soft plastics on the bottom in the deeper channels and holes.

If you have a boat, you can fish the main channel, the deeper holes, and the open water beyond the harbor mouth. Drifting with live bait or jigging with soft plastics works well for flounder. Stripers can be found along the channel edges and around structure — rocks, pilings, and drop-offs. The river itself (upstream from the harbor mouth) holds smaller stripers and schoolies, especially in summer.

Timing matters. Fish are most active on moving tides — the first two hours of incoming tide and the last two hours of outgoing tide are usually best. Slack water (the brief period between tides) can be slow. Early morning and late evening are more productive than midday, though summer schoolies will bite all day.

Regulations and Licenses

You need a Massachusetts saltwater fishing license to fish in Green Harbor. You can buy one online through the Massachusetts Division of Marine Fisheries website or at many tackle shops. A one-day license costs less than a full-year license, so choose based on how often you plan to fish.

Striped bass have a minimum size of 18 inches and a daily limit of one fish per person (as of the most recent regulations, though this can change). Flounder (summer flounder) have a minimum size of 19 inches and a daily limit of four fish. Check the current regulations on the Division of Marine Fisheries website before you go, because size and bag limits can shift year to year.

If you want to dig clams or quahogs, you need a shellfishing permit from the Town of Marshfield. Contact the Marshfield Board of Selectmen or the harbormaster's office to find out how to get one. Permits are usually inexpensive and may be daily, seasonal, or annual. There are also harvest limits and size requirements for shellfish — the town will provide those details when you get your permit.

Access, Parking, and Facilities

Green Harbor has public parking near the harbor entrance, with spaces for both cars and trailers. The lot is managed by the town and fills up on summer weekends, so arrive early if you are going on a Saturday or Sunday. There is a public boat launch with a fee (usually a few dollars per launch, though rates vary by season).

You can fish from the jetties without a boat — they are accessible from the parking area and offer good casting distance into the harbor and toward the mouth. The shore around the harbor also has spots where you can walk out and fish, though some areas are private property, so stick to public access points.

Facilities include restrooms near the parking area and a few small shops and restaurants within walking distance. There is no bait shop directly at the harbor, so bring your own bait or buy it before you arrive. The nearest tackle shops are in nearby towns like Marshfield Center or Duxbury.

What Makes Green Harbor Different

Green Harbor is a hybrid — part river, part open bay — which means you get different fishing depending on where you focus. The river holds smaller fish and schoolies, especially in summer, while the bay mouth and open water hold larger stripers and more flounder. This variety means you can adjust your target based on what you want to catch and how much time you have.

The harbor is also less pressured than some nearby spots like Plymouth Harbor or Cape Cod Canal, so fish can be less wary. The tidal range is significant (around 9 feet), which creates strong currents and good feeding windows. If you time the tide right, you can have excellent fishing in a short window.

Shellfishing adds another dimension — if you have a permit, you can combine a fishing trip with clamming or quahogging, especially in summer and fall. This makes Green Harbor a good choice if your group has mixed interests.

Frequently Asked Questions

What is the best time of year to fish Green Harbor?

Spring (April–May) and fall (September–October) are most productive for striped bass. Summer is best for flounder and schoolies. Winter is slow and less comfortable. If you want the most consistent action, go in September or early October when water is cooling and larger stripers are moving through.

Do I need a boat to fish Green Harbor?

No. You can fish from the jetties and shore without a boat and catch stripers and flounder. A boat gives you access to deeper water and more ground to cover, but it is not required. Shore fishing is often best on moving tides when fish move into shallower water.

Can I keep striped bass I catch at Green Harbor?

Yes, if the fish is at least 18 inches long. You can keep one fish per day. Check the current regulations on the Massachusetts Division of Marine Fisheries website before you fish, because size and bag limits can change.

Where do I get a shellfishing permit?

Contact the Town of Marshfield Board of Selectmen or the harbormaster's office. They will tell you the cost, how long the permit is valid, and where you can dig. Permits are usually inexpensive and available for daily, seasonal, or annual use.

What should I bring to fish Green Harbor?

Bring a saltwater fishing license, appropriate tackle for stripers or flounder (live bait or lures), a tide table or app to time your fishing, and weather-appropriate clothing. If you are fishing from jetties, wear shoes with good grip. Bring water and snacks — there are limited facilities at the harbor itself.