Three Oaks Scuba Zone

Three Oaks in Crystal Lake offers clear water, easy entries, and a simple layout that works well for training and practice. This is my closest local quarry and the place I dive most often, so the notes below reflect firsthand experience. Expect three permanent platforms, a few small attractions, and a friendly community vibe.

• Considered by many to be better than Haigh for clarity but not as full of attractions as Pearl.
• Generally open from dawn to dusk between late April or early May and early or late October, depending on weather.
• Temperatures are often near 60 F at depth. Most divers use at least a 5 mm; a 7 mm or drysuit is recommended in April, May, and October.
• No on site shop or fills. Bring cylinders ready to go and your own emergency O2 plan.
• Buddy required by park rules. Solo certifications are not accepted.
• Stay inside the buoyed scuba zone. Boats with trolling motors use the lake, and there is little to see outside the zone.
• Park rules call for a dive flag. Many divers float an SMB tied to Platform 1 to indicate divers are down.
• Two shops are within 5 minutes for fills and rentals; both are typically closed on Sunday:
  • Sea Level Diving (just outside the park)
  • Crystal Blue Diving (under 5 minutes away)
• Gentle sloping gravel beach entry and a dock suitable for practicing giant strides.
• Common sightings include bass, pike, bluegill, and a resident catfish.

• Most Saturday and Sunday mornings in season you will see OW checkouts and other classes.
• Several evenings a week, Sea Level Diving offers an after work fun dive with a guide or divemaster:
  • Limited to 6 people due to provided transport from the shop.
  • Pre registration required.
  • Cost is about $30 including the park dive fee.
  • No buddy required.
  • Be checked in at the shop by 5:45 pm.
  • Rental gear not included.

Step 1: Pay for parking at the gate (about $5 per day).
Step 2: Keep left as you enter the lot and continue around toward the boat launch area.
Step 3: Walk to the boat launch building, go to the outside window, and tell staff you are here for scuba diving.
Step 4: Show your Open Water card, sign the waiver, and pay about $20 for the day. The website notes they may hold your card; in practice they usually just verify it.
Step 5: Unload in the lot and set up on the park benches. Some drivers briefly pull closer to unload, but it is not officially permitted.
Step 6: Have fun.
Step 7: Before leaving, notify staff at the boat launch window that you are out of the water.

Download PDF

Dive Map as of June 2025

• Buoys, boats, and attractions can shift, so use the map as general reference.
• Maximum practical depth is about 40 ft.
• Three permanent platforms, each roughly 10 x 10 ft, about 25 ft deep and spaced near 100 ft apart.
• Platform 1 is an easy swim of about 100 ft from the beach and has a buoy to aid descent.
• A basic buoyancy course, several culverts for short swim throughs, and two small row boats provide variety.
• As of winter 2023, you can start at Platform 1 and complete a full circuit on lines, roughly 800 ft in 20 minutes or about half an AL80.
• While decompression is not needed at these depths, many divers practice a safety stop on the Platform 1 downline before exiting upslope to the gravel beach.