The 13-Mile Loop Around the Island for Mercer Island Circ…

The 13-mile circumnavigation of Mercer Island is Lake Washington’s classic long route. The island sits in the center of the lake — 4 miles long, about 2 miles wide — and paddling all the way around puts you through open-lake crossings, residential shoreline, and views in every direction: Seattle skyline to the west, the Cascades to the east, and the I-90 bridge at both the north and south ends of the island.

Launch Options

Luther Burbank Park (on Mercer Island): The only convenient public launch on the island itself. Small beach access with carry-in for boards. Parking in the park lot — free but limited on busy days.

Address: 2040 84th Ave SE, Mercer Island, WA 98040

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Magnuson Park (Seattle side): Launch from Magnuson, cross east to Mercer Island (about 1.5 miles of open lake), and begin the island circumnavigation. Adds distance but gives you more parking options and a warmup crossing.

The Route

Most paddlers go counterclockwise: south from Luther Burbank, around the south tip of the island (passing under the I-90 bridge), up the west shore (facing Seattle), around the north tip, and back down the east shore to Luther Burbank.

The west shore is the most exposed — wind from the southwest hits it directly and boat traffic from the main lake channels runs along this side. The east shore is more protected and quieter. Plan to be on the west shore in the morning when winds are lightest.

What to Expect

I-90 bridges: Two I-90 floating bridges (the old and new spans) cross the lake at the south end of the island. Paddling under the bridges is part of the route — watch for motorboat traffic in the channel between the spans.

Shoreline: The island is almost entirely residential. No services or restrooms en route. The entire shoreline is private except for Luther Burbank Park and a few public beach access points on the east shore.

Logistics

• Time: 4-6 hours depending on pace and conditions — a committed half-day to full-day outing
• Conditions required: Calm day essential. Wind above 10 knots makes the west shore crossing uncomfortable. Check the forecast and have a bail-out plan (Luther Burbank is your only realistic exit point).
• Skill level: Intermediate to advanced. Open lake crossings, exposure to wind and motorboat traffic, no services mid-route.
• Food and water: Bring everything you need. No stops on the island for non-residents.