Mount Baker Beach is a lifeguarded public swimming beach run by Seattle Parks and Recreation on the west shore of Lake Washington, in Seattle's Mount Baker neighborhood. It sits at the lake end of Mount Baker Park, an Olmsted-designed ravine park that runs down from South McClellan Street, with Colman Park wrapping the shoreline just to the north. Both parks were listed together on the National Register of Historic Places in 2020. Looking north from the sand you can see the I-90 floating bridge.

The city lists the beach at 2521 Lake Park Dr S. The bathhouse and the small parking lot beside it are on Lake Washington Boulevard S, at the bottom of the hill. Spaces are limited, so on a hot day plan on walking or biking in. A wide path runs downhill through Mount Baker Park from the neighborhood above, and Lake Washington Boulevard is a popular bike route. The park is open 6 a.m. to 10 p.m.

The swim area is a short stretch of sand and fine gravel with a roped-off section of lake. Seattle Parks lists a floating swim platform with a 1-meter diving board. The board depends on water depth, which changes over the season. A long wooden fishing pier runs out from the shore next to the swim area. Lake Washington is cold in June and usually warms up through July and August. Lifeguards work from late June through Labor Day. In past seasons their hours have been noon to 7 p.m. on weekdays and 11 a.m. to 7 p.m. on weekends, weather permitting. The city posts each summer's dates in the spring. Swimming here costs nothing. Seattle Parks runs the lifeguarded beaches as free swimming, and the free youth swim lessons (ages 6 to 16) are offered at this beach too.

Check conditions before you go. Public Health - Seattle and King County tests the water weekly from mid-May to mid-September and closes beaches when bacteria run high. Mount Baker Beach was closed to swimming in mid-July 2026 after elevated bacteria results, and it has also been closed for a sewage spill in the past. Signs go up at the shore when a closure is in effect. In June 2026, fire crews pulled a missing swimmer from the cold water here, so swim inside the roped area and stay off the platform when no lifeguard is on duty. On July 23, 2025, a fire destroyed the north wing of the bathhouse. Because the restrooms were out of service, the city ran no lifeguards here for the rest of that summer. Emergency repairs reopened the restrooms for the 2026 season, and a full bathhouse renovation is planned after that.

Away from the water, Mount Baker Park has tennis courts, a playground off S. McClellan St., drinking fountains, and paths shaded by maples and chestnuts, with a restroom partway up the slope. The 1911 Japanese stone lantern given to the city by a Kobe businessman stands near the lake end. Colman Park's trails and terraces start right next door. The beach doesn't empty out entirely in winter either, since local groups hold polar bear plunges here.