Fort Peck Dam Tailwaters offers a challenging freshwater diving and snorkelling experience in the United States. Located near Fort Peck Lake, the site features depths ranging from 30 to 40 metres. Divers and snorkellers must contend with strong currents and cold water temperatures, which typically average 12.2°C and reach a maximum of 17.0°C. Due to these demanding conditions, the site is suited for advanced divers. Access is available via both shore and boat entries. On-site facilities include parking, toilets, and showers to support visitors. The site is noted for its distinct water conditions compared to the main reservoir.

Duck Creek Campground provides a shore-entry snorkel site located on Fort Peck Lake. The area features a relatively shallow bay where snorkelers can observe aquatic vegetation along the shoreline. Conditions are generally mild, though water temperatures vary significantly by season. In early April, temperatures are approximately 37-38°F (3-4°C), necessitating thermal protection. The primary swimming season occurs during July and August when water temperatures reach an average of 68.7°F. Snorkelers should remain aware of boat traffic in the vicinity. Facilities at the site include parking and toilets.