Boating & Things to Do in Grassy Key
Discover 2 amazing destinations, from hidden anchorages to lively sandbars.
Best Time to Visit
Subtropical climate featuring mild, dry winters and warm, active summers perfect for sandbar rafting and reef snorkeling. Boaters generally favor the November to May window for the most stable cruising conditions.
Winter (Dec – Feb)
Air: 74°F – 78°FWater: 71°F – 73°F
Cool offshore breezes, excellent visibility for reef snorkeling.
Spring (Mar – May)
Air: 81°F – 85°FWater: 76°F – 78°F
Sandbar season begins, prime offshore sportfishing conditions.
Summer (Jun – Aug)
Air: 88°F – 92°FWater: 83°F – 86°F
Warm waters, afternoon thunder showers, lobster season opens in late July.
Autumn (Sep – Nov)
Air: 82°F – 86°FWater: 79°F – 82°F
Tropical season transitions to pleasant autumn cooling.
Events Calendar
No upcoming seasonal events registered for Grassy Key yet.
Recommended Voyages & Itineraries
Curated Route4 Days
Biscayne Bay to Key Largo Cruise
Cruise south from Miami's high-energy sandbars through Biscayne National Park. Stop at Elliott Key, snorkel Carysfort Reef Lighthouse, and dock-and-dine in Key Largo.
Planned Stops
Miami→
Nixon Sandbar→
Elliott Key→
Carysfort Reef→
Key Largo
Browse by Activity
All Grassy Key Destinations
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SANDBAR
Grassy Key Sandbar
4.8
Grassy Key
Grassy Key Sandbar, also known as Valhalla Sandbar, is located just east of Marathon next to Grassy Key. Boasting a clean, shallow sandy bottom and calm waters, this is Marathon's most popular sandbar destination for boaters looking to relax and socialize.
SNORKEL
Bronze Pin Wreck
4.6
Grassy Key
Named for the bronze fasteners found during its archaeological documentation, the Bronze Pin Wreck lies in the shallow sand and seagrass flats on the northern edge of Hawk Channel off Grassy Key. Resting in only 14 feet of water, this is an excellent, calm snorkel site where visitors can view iron frames ranging from 2 to 6 feet long and observe local marine life in the surrounding seagrass.