Mercer Island Beaches

Mercer Island offers several options for public access to Lake Washington.

As you head to the Mercer Island shoreline this summer, stay alert to hidden dangers. The Mercer Island Police Department’s Marine Patrol Unit actively patrols the coast to keep the public safe and has already removed tons of debris left by recent flooding. However, submerged hazards may still be present, risking entanglement or drowning.

Remember that Lake Washington remains deceptively cold beneath the surface, which can quickly trigger muscle failure or hypothermia, even if the air temperature is in the eighties or nineties. Preventable drownings remain elevated across King County, with Lake Washington accounting for nearly 30% of recent open-water fatalities. Exercise caution by never swimming alone, using a life jacket, staying close to shore, and swimming in a designated swim area. Visit King County's website for more tips to swim safely.

For current water temperatures and water quality results, visit King County's Lake Swimming Beach Bacteria and Temperature page.

General Information

Lifeguards: Mercer Island beaches are not staffed by lifeguards. Swim at your own risk.
Dog Rules: Dogs and other pets are not allowed at public swim areas from May 1 to September 30. During the rest of the year, dogs are allowed on the beach but must be leashed at all times. Learn more about Mercer Island's off-leash dog areas here.
Group Use: If you’re interested in bringing a large group to a beach during the summer, you may need a Special Event Permit. Learn more here. Please note – Bus parking is not permitted at beach park parking lots. More information about buses is provided on park pages linked below.
Picnic Areas: Picnic areas operate on a first-come, first-served basis. Reservations for groups of 50 or less are available between May 1 and September 30. Learn more here.
Water Quality: During swimming season (May-September), King County Parks regularly tests water quality at lake beaches across the County, including the swim beach at Luther Burbank Park and Groveland Beach Park. Results are posted online by King County, and, when results exceed acceptable standards, the City posts signage at the park. The City has conducted its own water quality testing program since 2003, and the results typically show very low qualities of bacteria in the water at Luther Burbank and Groveland.