John D MacArthur Beach State Park - Florida Keys

MacArthur Beach State Park isn't your typical Keys dive, and that's precisely why we love it. Forget the deep reefs for a moment; this is a place to slow down, to really look. We're talking shallow, mostly sandy bottom with patches of seagrass, a perfect hunting ground for spotting the small stuff. We often find ourselves drifting along, eyes peeled for the incredibly camouflaged seaweed blennies or the skittish sheepshead minnows darting through the blades. Visibility can be a bit variable, especially after a good blow, but when it’s calm, the sunlight filters down, illuminating little worlds. Our favourite moments here are watching common snook cruise the edges of the grass beds, or spotting the flash of a barracuda zipping through a school of broad-striped anchovies. You’ll see plenty of mojarras kicking up sand, and if you’re patient, a sponge cardinalfish might just peek out from its hiding spot. It’s a gentle, unassuming dive that rewards curiosity. This spot is ideal for macro photographers or anyone who enjoys a relaxed, exploratory dive. We’d suggest going at high tide for the best conditions and easiest entry. You won't find dramatic drop-offs, but you will find an abundance of life thriving in the shallows.

Location
Florida Keys, United States, North America
Coordinates
26.823960, -80.042625
Type
shore
Maximum Depth
3-12m

Marine Protected Area: Phil Foster

Best Time to Dive in Florida Keys

The warmest water temperatures in Florida Keys occur in July, averaging 31.5°C (up to 34.8°C). The coolest conditions are in January at 19.3°C.

Monthly Water Temperatures

  • January: 19.3°C (air: 18.5°C)
  • February: 20.5°C (air: 21.6°C)
  • March: 23.1°C (air: 22.4°C)
  • April: 25.5°C (air: 24.3°C)
  • May: 27.8°C (air: 25.9°C)
  • June: 30.2°C (air: 27.5°C)
  • July: 31.5°C (air: 28.3°C)
  • August: 31.5°C (air: 28.3°C)
  • September: 30.2°C (air: 27.3°C)
  • October: 27.3°C (air: 26.0°C)
  • November: 24.1°C (air: 22.3°C)
  • December: 20.9°C (air: 19.8°C)

Nearby Dive Sites in Florida Keys

Nearest Dive Centres to John D MacArthur Beach State Park

Marine Life in Florida Keys

Home to 91 recorded species including 69 reef fish, 6 sharks & rays, 3 other, 3 hard corals, 2 sea snails & nudibranchs, 2 sea urchins.

Notable Species

Recommended Packing List for John D MacArthur Beach State Park

Based on average water temperature of 26.0°C, currents 1 cm/s.

  • Shorty or Rashguard - warm 26°C water needs minimal exposure protection
  • Mask - essential for every dive
  • Fins
  • BCD - buoyancy compensator
  • Regulator - your most safety-critical piece of gear
  • Dive Computer - tracks depth, time, and NDL
  • Surface Marker Buoy (SMB) - essential for boat pickups
  • Dive Torch - useful for crevices and colour at depth
  • Underwater Camera - capture your diving memories