Coffins Patch is a shallow coral reef system in the Middle Florida Keys, located about 4 miles off Marathon near Key Colony Beach. It’s part of a protected Sanctuary Preservation Area known for some of the best snorkeling in the Florida Keys. The reef’s eerie name comes from an old ship wreck, rumored to have been carrying coffins when it ran aground on this spot. No actual coffins were ever found, but the legend stuck! A large stake still protrudes from the reef – local lore says it’s part of the old ship’s wreckage, marking the center of Coffins Patch.
With calm, clear water and vibrant marine life, Coffins Patch offers an accessible and family-friendly reef experience. Its shallow depths and plethora of sea creatures make it great for snorkelers and novice divers looking to explore a coral reef up close and personal!
This guide covers everything you need to know for a Coffins Patch snorkel or dive trip – from location and conditions to wildlife sightings, local insights, and tips to make the most of your snorkel or dive trip.
Coffins Patch Overview
| Aspect | Details |
|---|---|
| Location | 4-6 miles off Key Colony Beach, Marathon, FL, Latitude: 24° 41′ 4.19″ N, Longitude: -80° 57′ 59.99″ W |
| Access | Commercial tours, public access, check Captain Hook’s |
| Depths | 5-25 ft, visibility 10-50+ ft |
| Marine Life | Nurse sharks, stingrays, eels, fish, corals (impacted by 2023 bleaching) |
| Activities | Snorkeling, diving, suitable for all levels |
| Conservation | SPA regulations |
| Best Visit Times | May-October is typically calmer, November-April cooler with more chop |
| User Feedback | Positive, diverse sea life, great for snorkelers & beginner diving |
Where is Coffins Patch? Location & Protected Status
Coffins Patch lies ~3.5–4.5 miles offshore from Marathon (Vaca Key/Key Colony area) in the Florida Keys. This cluster of patch reefs spans about 248 acres within the Florida Keys National Marine Sanctuary. Coffins Patch is designated as a Sanctuary Preservation Area (SPA). This means the reef is federally protected. No fishing, spearfishing, or collecting of marine life is allowed here.
Latitude: 24° 41′ 4.19″ N
Longitude: -80° 57′ 59.99″ W
Reef Features & Underwater Landscape
Coffins Patch isn’t a single reef. It’s a collection of about six distinct patch reefs that all have their unique quirks. Notable sites within Coffins Patch include “The Stake” (named after the angled steel post visible above the water) and “The Aquarium”. These are two popular locations for snorkel trips in the Marathon.
Depth and Terrain
The area is very shallow with depths ranging from roughly 5 to 25 feet across the patches.
Some coral heads even rise near the surface. The reef features sandy bottoms dotted with hard corals. We often see big boulder and brain corals and lush soft corals like sea fans and gorgonians waving in the current. These soft corals and sea fans create vibrant scenery for snorkelers.
Larger coral formations top out around 5–10 feet below the surface, while deeper sand channels may reach ~20–25 feet on the edges.
This topography is perfect for snorkelers (who can easily see the reef from the surface) and also allows adventurous free-divers or novice scuba divers to explore nooks and crannies on the reef floor.
Visibility & Conditions
Thanks to its offshore location near the Atlantic reef crest, Coffins Patch often enjoys excellent water clarity. On calm days, visibility can easily be 50+ feet, revealing the full beauty of the coral and fish below. Currents are typically pretty calm here. That’s why this is also one of the best places to dive in all of the Florida Keys.
The shallow depth also means more sunlight which really helps snorkelers see a colorful environment below. With that said, conditions always vary with weather – wind or storms can stir up waves and reduce visibility. Pick a calm day for the best experience.
What Kind of Fish Will You See at Coffins Patch?
Tropical Fish
Coffins Patch has no shortage of colorful tropical fish. Snorkelers commonly encounter schools of blue tangs, sergeant majors, angelfish, parrotfish, butterflyfish, and many others swimming around the coral below.
On a single outing you might easily spot 20+ fish species ranging from small damselfish to larger reef fish. Brightly colored queen angelfish, stripy yellow sergeant majors, and iridescent blue parrotfish are just a few favorites that add splashes of color to the your trip.
Larger Sea Creatures
The reef’s healthy habitat attracts plenty of bigger marine life as well.
- Keep an eye out for stingrays gliding over the sand and spiny lobsters hiding under ledges.
- We commonly see Grouper, snapper and barracudas throughout this reef as well.
- You might even see a curious moray eel peeking from a crevice.
- Nurse sharks also frequent Coffins Patch. These lazy sharks often nap on the bottom and may peacefully swim by snorkelers (they are not aggressive to humans so don’t worry!).
- Lucky visitors have even sighted sea turtles and the occasional eagle ray passing through.
Coral and Plant Life
- Coffins Patch has a mix of hard coral like brain, star, and boulder corals.
- You’ll also see plenty of soft coral like sea fans, sea whips, and rod corals that sway with the water.
- You’ll also notice various sponges (tube and vase sponges in orange, purple, etc.) and patches of seagrass or algae on the substrate.
Historically, this area was known for stands of rare pillar coral as well though many corals have suffered recent bleaching (more on that in a later section).
Snorkeling at Coffins Patch – What to Expect
Coffins Patch is often touted as a perfect snorkel site for beginners and families because of its shallow depth and typically gentle conditions. Much of the reef lies just a few feet below you, so you can float on the surface and see plenty without diving down. The shallow areas (5–10 ft) allow even novice swimmers to feel comfortable while observing fish and corals with a problem.
While snorkeling, you’ll drift over beautiful coral heads. There will be plenty of fish darting in and out of the coral. Freediving down a few feet can reward you with a closer look. Even at only 10–15 feet deep, you can inspect the base of coral heads where lobsters or eels might hide.
The water is typically warm (in the 80°F range in summer), and you can comfortably spend an hour or more exploring the patch reefs. Many snorkelers are surprised by how much there is to see even in such shallow water.
Gear and Safety – What Do You Need to Bring?
Standard snorkel gear (mask, snorkel, fins) is sufficient. Bring a dive flag if snorkeling from a private boat. Florida law requires a “diver down” flag when people are in the water. Wearing a snorkel vest is a good idea for added buoyancy if you’re not an experienced swimmer.
Bonus Tip: Use reef-safe sunscreen or wear a rash guard to protect yourself from the sun – and to protect the reef. Chemicals from the sunscreen wash off your body and contribute to coral bleaching. Also, never touch or stand on the coral. You can easily damage coral
Scuba Diving at Coffins Patch
Certified divers can also enjoy Coffins Patch, though the shallow max depth (~20–25 ft) means this is more of a relaxed, easy dive than a deep exploration. It’s a great dive site for beginner divers or training dives.
It’s also an awesome place to go if you’re into underwater photography. The protected reefs and shallow depths really look awesome with all of their color. You can do long bottom times here due to the shallow depth and still have air to spare.
There is usually minimal current at Coffins Patch, making it easy to stay with your group and near the boat. Visibility is generally very good, though divers will stir up sand if you kick too close to the bottom. Overall, divers will find Coffins Patch a low-stress, high-reward site for viewing the Keys marina life.
How to Get to Coffins Patch
Coffins Patch is only accessible by boat. It’s a few miles offshore, so you will need to either go with a snorkel tour company or have access to a private boat. Kayaking or paddleboarding that far offshore is not advisable for most people. Strong winds, currents, distance and boats can make it dangerous.
Commercial Tours to Coffins Patch
The easiest option is to book a commercial snorkel tour out of Marathon or Duck Key. Numerous tour operators run half-day trips to Coffins Patch. These tours typically provide all gear, boat transport, and a guide, making it stress-free. You’ll visit 2–3 dive sites for about an hour each.
How to Get to Coffins Patch on Your Own Boat
If you have your own boat or a rental, you can navigate to Coffins Patch yourself. Coordinates are marked on nautical charts and many GPS units. There are usually multiple white mooring balls on the site to anchor your boat. Do not anchor on the reef under any circumstances. Anchoring on living coral is illegal in the SPA. Tie up to a mooring buoy and double-check it’s secure. Display a dive flag when people are in the water. If you’re not very experienced with boating in the Keys, consider the tour option. It’s easy to accidentally damage seagrass beds or coral heads and incur hefty fines in protected zones. Going with a guided trip your first time can show you the ropes.
Best Time to Visit
It’s pretty simple. Calm weather = Best snorkeling. The weather and sea conditions will greatly impact your Coffins Patch experience. The best time to go is on days with low wind and calm seas when the water is flat and clear. Generally, the late spring through summer months offer warm water and many calm days. In winter, cold fronts can bring strong winds that make the ocean choppy (and can cancel boat trips). November – March tends to be windier and can have rougher conditions, while April – October usually has more favorable snorkeling weather (aside from storm events).
What is the Best Time of Day to Snorkel or Dive?
Morning trips are often ideal. Winds are often lighter in early mornings, but this varies pretty widely. Many tour operators run trips around 8:30 AM and again around 1 PM. If you go in the middle of the day, be mindful of the sun’s intensity and reapply reef-safe sunscreen or wear UV protective clothing.
Is Coffins Patch Crowded?
Coffins Patch sees less crowding than the famous Sombrero Reef, but it’s still a popular spot. On a perfect-weather day, you might find a handful of tour boats and private boats moored there. To avoid any crowds, try going on a weekday rather than weekends, or earlier in the morning. That said, even when other boats are present, the area is spread out over multiple patch reefs. It rarely feels overly crowded in the water and there is plenty to see!
Top Tips for Snorkeling & Diving at Coffins Patch
- Use the Mooring Buoys: Always hook onto a mooring buoy when one is available at the reef.
- Mind the Regulations: Remember that all fishing and collecting is prohibited at Coffins Patch.
- Reef Etiquette: Practice good reef etiquette to keep Coffins Patch healthy. Do not touch, stand on, or kick the corals.
- Let the fish come to you: The marine life in Coffins Patch knows they’re in a safe place. Take moments to just be still and watch as the fish come close to you (especially diving).
How Does Coffins Patch Compare to Other Reefs?
Coffins Patch vs. Sombrero Reef
These are the two most popular snorkel spots in Marathon. They’re also great beginner dive sites. Sombrero Reef (marked by its lighthouse) has impressive “finger” coral formations in 15–30+ ft of water. They’re really an awesome site and one of the more unique experiences in Marathon.
Coffins Patch is shallower, more sheltered, and often less crowded. Many of the snorkelers on our snorkel and dive trips appreciate this. Coffins Patch’s coral is spread over patch reefs with lots of fish in the 5–15 ft range. If you have time, do both. If you prefer calmer conditions and an easier snorkel experience, I’d go with Coffins Patch. If you’re diving, I’d go with Sombrero.
Coffins Patch vs. Alligator Reef (Islamorada)
Alligator Reef (about 50 miles northeast) is another well known shallow reef in the Upper Keys. It’s similar in depth (5–20 ft) and marine life to Coffins Patch. Alligator is a larger reef structure. One advantage of Coffins Patch is that it’s closer for those staying in Marathon. Both are SPAs and offer great snorkeling. If your Keys trip spans multiple regions, they’re both worth visiting.
Other Sites Nearby
You might also hear about Hawk’s Cay Sandbar or Grassy Key Sandbar. These are popular for a post-snorkel swim in the beautiful turquoise water. Some tours combine a Coffins Patch snorkel with a stop at a calm sandbar for a fun dual excursion.
Wrapping Up: Coffins Patch is an Awesome Beginner Dive Site & Snorkel Location
Coffins Patch remains a must-visit spot for snorkelers and divers exploring the Middle Keys. Its combination of shallow, clear water and thriving marine life is a no-brainer selection.
Whether you’re a first-time snorkeler or a seasoned diver, this reef will have something to see! For more information about diving and snorkeling in the Florida Keys, or to book a trip, you can reach out to Capt. Hook’s Marina and Dive Center. We offer daily snorkeling and scuba dive trips in Marathon.
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