Cedar Island is a freshwater reef site located off the west shore of Flathead Lake near Rollins. The site is known for its rock formations along the southern edge and high water visibility, which often ranges between 15 and 30 metres. Access to the island requires a boat. Divers and snorkellers should be prepared for cold water, with surface temperatures reaching 21 degrees Celsius in summer, though temperatures drop into the low teens past the thermocline at 18 metres. Due to the depth and potential for cold water, this site is best suited for intermediate-level divers. Be aware of boat traffic in the area. Toilets are available at the site.

Big Arm Bay in Flathead Lake is a long, shallow pebble beach offering accessible entry for divers and snorkellers. The site features a shallow lake floor that remains at an average depth of 4 metres, with a maximum depth of 8 metres. Conditions are generally mild, with visibility ranging between 15 and 30 metres. This location is suitable for beginners and families, with typical dives lasting around 45 minutes. Facilities at the site include parking, toilets, and showers. Due to the freshwater environment, divers should be prepared for cold water temperatures, which vary significantly outside of the summer months.

Goose Island is a glacial rock outcropping in Flathead Lake featuring a topography of large boulders and submerged logs. This site is accessible only by boat and is suited for intermediate snorkelers. Depths range from 5 to 18 metres, with an average of 12 metres. Visibility is generally good, ranging between 15 and 30 metres. Divers and snorkelers should be aware of significant thermoclines, as temperatures drop to 10 to 15 degrees Celsius at 18 metres. Hazards include cold water, entanglement risks from submerged logs, and boat traffic. Typical sessions last around 45 minutes.

West Shore in Flathead Lake features a unique underwater landscape defined by glacially carved dolomite outcrops. Divers and snorkellers encounter submerged boulders and ledges throughout the site. The area is suitable for beginners, with depths ranging from 2 to 10 metres and an average depth of 6 metres. Access is via the shore, and conditions generally include mild currents and visibility between 15 and 30 metres. Divers should be aware of potential hazards including boat traffic, entanglement risks, and cold water thermoclines. Facilities at the site include parking, toilets, showers, changing rooms, a rinse station, air fills, equipment rental, and a cafe.

Yellow Bay in Flathead Lake offers a wide, gravelly beach entry suitable for beginners. Located within the cherry orchards, the site features a lake floor that drops off quickly into deeper water. Snorkelers can expect mild currents and a typical in-water duration of 45 minutes. The site is accessible directly from the shore, with the primary area of interest located approximately 5 metres from the water's edge. Due to the nature of this freshwater environment, divers and snorkelers should be prepared for cold water conditions. This site is well-regarded for its accessibility and topography, providing a straightforward experience for those exploring the lake.

Finley Point, located on the southern end of Flathead Lake, provides a freshwater diving and snorkelling environment featuring a mix of sandy and rocky bottoms. Divers and snorkellers can expect mild currents and visibility ranging from 5 to 20 metres. Shore access is available, and the site is suitable for beginners. Facilities at the location include parking, toilets, and showers. The water is considered very cold outside of the swimming season, which runs from June through September. Typical dives last approximately 30 minutes. Due to the cold water, appropriate thermal protection is recommended for all in-water activities.

Salish Point in Polson is a public swimming area within Flathead Lake that offers a controlled environment for beginners. The site features a rocky bottom and several docks that provide structure for the local freshwater habitat. Divers and snorkellers can expect visibility ranging from 6 to 15 metres. Entry is via the shore, and the site is characterised by mild currents. Due to the nature of this freshwater location, water temperatures remain cold, so appropriate thermal protection is recommended. Facilities at the site include parking and toilets for visitor convenience.

Woods Bay provides a convenient shore entry point for snorkelling in Flathead Lake near Bigfork. The site features a concrete ramp and a small beach area, offering accessible entry for beginners. Conditions at this location are generally mild, though the area experiences a high volume of boat traffic. Snorkellers should remain vigilant of vessels while in the water. Visibility is typically good, though the site is less secluded than nearby state parks. This location is suitable for those seeking a straightforward entry into the freshwater environment of the lake.