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Idylwood Beach Park

Other Link Idylwood Tree Restoration Project

Idylwood Beach Closed

Update: Idylwood Beach is still closed due to high bacteria levels. King County retested on Friday and bacteria levels had dropped significantly. Another sample will be taken today with results expected Wednesday. We plan to reopen on Wednesday if results stay within the safe range per King County protocol.

Crews from the King County Water and Land Resources Division tested the water earlier this week and found that the levels of E. coli on the beach exceeded the thresholds for opening. The typical cause of high E. coli levels in swimming water is generally related to waterfowl in the area. King County crews will sample the beach again tomorrow and next Monday, June 24. Per King County protocol, the beach will remain closed through the weekend. The beach will reopen when E. coli levels return to a safe range.

Updates about the Idylwood Beach closure will be posted to here.

Additional Resources and Questions

What if I swam at Idylwood Beach recently?

An increased risk of recreational water illness (RWI) can come with contact or ingesting contaminated water. Gastrointestinal issues are the most commonly reported symptoms of ingesting contaminated water. Onset of symptoms could take up to two weeks to appear after contact. Call your medical provider if you notice changes in your health.

What are the recorded E. coli levels at Idylwood Beach?

What is the King County beach closure protocol?

How does bacteria get into lakes?

King County swimming beach FAQ’s

Map of all swimming beach bacteria levels

Located on the shores of picturesque Lake Sammamish, Idylwood features a swimming beach, including a bathhouse and restrooms. Launch your car-top boat from the park’s small ramp. Spread out and play a game in the large open space or explore Idylwood’s playground area. Picnic shelters and picnic tables complete the picture for a perfect get-together.


  • 18 acres


  • Canoe Launch 
  • Facility Rental 
  • Fishing
  • Natural Areas
  • Parking
  • Picnic Shelter Picnic Tables 
  • Play Area
  • Restrooms
  • Swimming Beaches 
    • Barbeques
    • Sand Volleyball