Big Blue (Mason City)

Iowa, United States

Depth

10m

Visibility

5m - 15m

Entry

Shore

Experience Level

Beginner

Big Blue (Mason City)

Iowa, United States

Depth

10m

Visibility

5m - 15m

Entry

Shore

Experience Level

Beginner

About Big Blue (Mason City)

Big Blue, located in Mason City, Iowa, is a freshwater dive site nestled in a 14-acre (5.7-hectare) lake formed from an old quarry. Situated in Lester Milligan Park, this site offers convenient shore access with a maximum depth of 10 meters (33 feet). While visibility varies, it can reach up to 15 meters (49 feet), making it a popular spot for divers, especially on weekends when many gather to explore its unique underwater features. The lake's warm waters and easy entry from the swimming beach make it a great location for both training and casual dives.

Underwater, divers can explore a variety of submerged attractions, including an old training platform at 4 meters (13 feet), several derelict vehicles on the lake's east side, and even a 7.6-meter (25-foot) sailboat. With no gas-powered motorboats allowed, the tranquil environment is often used by local emergency personnel for training exercises. Additionally, the park offers amenities like a shelter house, restrooms, and playground equipment, making it an ideal destination for a family-friendly day trip from nearby cities.

Big Blue (Mason City) Dive Info

Terrain & Features

Inland, Other

Entry Type

Shore

Max Depth

10m

Visibility Range

5m – 15m

Experience Level

Beginner

Best Gas Mix

21%

O₂

CNS Load (45 min)

7% at 8m / 36%

O₂

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Marine Life

Bluegill
Crappie
Largemouth Bass
Northern Pike
Trout

Weather Conditions

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Dive Operators near Big Blue (Mason City)

High Adventure Scuba & Travel
87.27km

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Location

Dive Site Hazards

Thermocline Buoyancy Shift — Sharp thermoclines can cause sudden buoyancy changes.
Instant Visibility Collapse — Sediment disturbance can eliminate visibility immediately.
Late Detection of Structures — Submerged structures may only appear at very close range.

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