Mermet Springs
BackMermet Springs presents itself as a full-service dive site and travel agency located in the unexpected landscape of Southern Illinois. This 8.5-acre, spring-fed quarry in Belknap has cultivated a strong reputation, evidenced by a high 4.9-star rating, attracting divers of all skill levels from across the Midwest. It operates as a multi-faceted establishment, functioning as a dive school, a gear store, a campground, and a unique adventure travel destination. The business is operational throughout the week except for Tuesdays and Wednesdays, with extended hours on Fridays and Saturdays to accommodate weekend trips.
The Diving Experience: Attractions and Conditions
The primary draw of Mermet Springs is, without question, its underwater environment. The quarry offers depths that range from a shallow 15 feet to a maximum of 120 feet, catering to both novice and experienced divers. One of the most lauded features is the collection of submerged attractions purposefully sunk to create a unique underwater playground. The centerpiece is a Boeing 727 passenger jet, famously used in the 1998 film U.S. Marshals. This 120-foot-long fuselage, resting with its nose at 50 feet and tail at 15 feet, allows properly certified divers to perform swim-throughs, an experience frequently cited as a highlight.
Beyond the iconic aircraft, the quarry is littered with other fascinating objects. Divers can navigate between a school bus, a semi-truck, an ambulance, two Cessna airplanes, a railroad car, and even a human-powered submarine. This curated collection of wrecks makes it an excellent location for specialty courses like PADI Wreck Diver certification and provides endless interest for recreational dives. The presence of numerous underwater training platforms at various depths (from 15 to 100 feet) further solidifies its status as a premier training facility.
However, potential visitors must be keenly aware of the water conditions. As several visitors have noted, the water can be quite cold. Temperatures vary significantly with the seasons and depth; they can be in the mid-80s Fahrenheit above the thermocline in summer but drop to the low 40s at depth, especially in winter. This makes a dry suit not just a recommendation but often a necessity for comfort and safety during deeper or longer dives. The facility acknowledges this by offering over 50 dry suits in its rental department, a crucial service for those unprepared for the chill. Visibility is generally good for an inland quarry, ranging from 15 to over 60 feet depending on conditions.
Aquatic Life
Adding to the experience is a surprising variety of freshwater life. The quarry is home to large bluegill, bass, crappie, and notably large albino catfish. The most unique inhabitants are the American paddlefish (also known as spoonbills), prehistoric-looking filter feeders that can grow to over five feet long. Mermet Springs offers one of the few clear-water environments in the world where divers can reliably encounter and photograph these massive fish. Sturgeon and even freshwater jellyfish have also been spotted, making each dive a potential encounter with unusual fauna.
Training, Facilities, and Staff
Comprehensive Dive Training
As a designated 'school,' Mermet Springs provides a wide array of scuba diving lessons. They cater to absolute beginners with "Try Scuba" classes, designed to give newcomers a safe and controlled first taste of the underwater world. Testimonials frequently praise the instructors, with beginners highlighting how guides made them feel safe and calm throughout the process. The facility offers a full path for scuba diving certification, from Open Water Diver courses all the way to professional instructor levels through agencies like SSI. For those already certified, it's an ideal place to pursue advanced training, with specialty courses like Deep Diving and Dry Suit Diving being particularly relevant to the site's conditions.
On-Site Amenities and Services
The surface facilities are a significant asset. Visitors consistently report that the amenities are clean and well-maintained. There are 18 covered pavilions with electricity and ceiling fans available for reservation, which are perfect for groups and for staging gear. The property includes heated shower houses and proper restrooms, a welcome comfort after a cold dive. The on-site dive shop handles air and nitrox fills and offers a comprehensive selection of rental equipment, ensuring divers have access to everything they need. For solo divers, the option to hire a knowledgeable dive guide is a major advantage, allowing them to fully appreciate the site without needing to arrange a buddy beforehand. The staff's friendliness and expertise are recurring themes in customer feedback, contributing significantly to the positive atmosphere.
Accommodations: Camping and Lodging
For those planning multi-day vacation packages or weekend trips, Mermet Springs provides on-site lodging options, though they come with certain limitations. The facility functions as a campground with options for both tents and RVs. Tent sites are first-come, first-served and include a fire ring. RV sites are also available and can accommodate large vehicles, providing a level spot and a 30-amp electric hookup.
A notable drawback for some travelers is the lack of more robust RV amenities. Critically, there are no on-site water or sewer hookups. While the clean shower houses and restrooms mitigate this to an extent, RV campers seeking full-service connections will need to manage their resources accordingly or consider off-site options. The business does provide a list of nearby hotels, Airbnbs, and resorts for those who prefer more comfortable accommodations.
Final Considerations for Potential Visitors
Mermet Springs has firmly established itself as a premier destination for inland diving in the United States. Its strengths are numerous: a unique collection of underwater attractions, a wide range of training opportunities with highly-rated instructors, and excellent, clean support facilities. The friendly and professional staff create a welcoming environment for divers from all backgrounds, including families, groups, and solo adventurers.
However, the key to a successful visit is preparation. The cold water temperatures at depth are a serious factor that should not be underestimated; appropriate thermal protection, such as a dry suit, is essential for enjoying the deeper attractions. Furthermore, while the on-site camping is convenient, the lack of full RV hookups is a practical limitation to be aware of. Overall, for divers in the Midwest and beyond looking for a reliable and fascinating place to get in the water, Mermet Springs offers a compelling and well-managed experience that stands out in the world of adventure travel.
