Pearl Lake features a technical wreck dive situated 10,000 metres from shore, requiring boat access. The site lies at depths between 70 and 80 metres, with an average of 75 metres. Divers encounter mild currents and visibility ranging from 10 to 30 metres. Water temperatures are cold, fluctuating between 2 and 14 degrees Celsius, with common thermoclines and temperatures often reaching 4 degrees Celsius at the bottom. Due to the significant depth and cold conditions, drysuit experience is strongly advised. Divers must manage risks including potential entanglement in wreck structures and overhead boat traffic. This intermediate-level dive requires a wreck certification.

The St Mary wreck in Pearl Lake offers an accessible freshwater dive for beginners. Resting at depths between 1 and 6 metres, the site features a consistent visibility of 30 metres, allowing for clear views of the structure from the surface. The site is located 50 metres from the shore and requires boat access. Divers should be aware of potential hazards including boat traffic, cold water, and entanglement risks. Due to water temperatures ranging from 2 to 22 degrees Celsius, adequate thermal protection is necessary. The site provides facilities including parking, toilets, showers, and changing rooms.

12th Street Beach at Northerly Island offers shore access to a freshwater site featuring an underwater steel bulkhead and the remains of a 1920s schooner hull. Located south of the Adler Planetarium, the site reaches depths of 2 to 6 metres with an average of 4 metres. Conditions vary, with moderate currents and visibility typically ranging between 20 and 25 metres. Water temperatures fluctuate significantly throughout the year, from 2 to 23 degrees Celsius, and divers should be aware of potential thermoclines. Hazards include boat traffic, cold water, entanglement risks, and surf. Facilities available at the site include parking, toilets, showers, and a rinse station.

Morgan Shoal is a 32-acre dolomite limestone shelf situated 90 metres from the shore of Pearl Lake. This site features a remnant of a 425-million-year-old coral reef, characterised by dramatic rock crevices and ridges. Divers can explore both reef and wreck topography at depths ranging from 1 to 6 metres, with an average depth of 4 metres. Access is via the shore, and the site is suitable for intermediate divers. Conditions vary, with visibility reaching up to 6 metres and water temperatures fluctuating between 2C and 22C. Hazards include boat traffic, cold water, entanglement, low visibility, and strong currents.

Promontory Point in Pearl Lake is a man-made peninsula featuring a historic limestone revetment. The north side offers a rock beach with a shallow, sandy bottom, making it suitable for beginner snorkelers. Divers and snorkelers can explore the limestone blocks that form the artificial reef structure. Depths at this site range from 1 to 10 metres, with an average of 5 metres. Conditions vary, with visibility typically between 3 and 15 metres and mild currents. Access is via a shore entry. Facilities available at the site include parking, toilets, showers, changing rooms, and a rinse station. Be aware of potential hazards including boat traffic, cold water, and surf.

Illinois Beach at Pearl Lake features a unique rocky and sandy lakebed, representing the only remaining beach ridge shoreline in the state. This freshwater site is part of the Lake Michigan Dune Section, offering geological formations for snorkelers to explore. Conditions vary, with depths ranging from 2 to 6 metres and an average of 4 metres. The site is accessed from the shore and is suited for intermediate snorkelers due to moderate currents, potential surf, and variable visibility between 3 and 10 metres. Water temperatures fluctuate significantly throughout the year, ranging from 2C to 22C, with the warmest conditions typically occurring in August.