Pine Lake Park is a 19-acre wooded park run by the City of Sammamish on the east shore of Pine Lake, an 85-acre lake at about 389 feet elevation on the Sammamish Plateau, roughly 20 miles east of downtown Seattle. The swim beach sits at the water's edge below the picnic area, with the swim area alongside a large floating wooden dock that doubles as a fishing pier. The rest of the shoreline is lined with private homes, so the park is the only public way to get into the water here.

The park address is 2401 228th Ave SE, Sammamish. 228th Ave SE is the plateau's main north-south road, and the park entrance is on its west side about 2 miles south of Sammamish City Hall. A paved drive leads down through tall firs and cedars to the parking lots, and short paths and a set of steps drop from the picnic area to the beach and dock. No parking fee is posted, but the lots fill quickly on hot weekends because the park also hosts ball games and summer events.

The beach itself is small and the shore is more packed gravel and dark sand than a broad sandy strand, so a lot of swimmers use the dock to get in. Pine Lake is a small lowland lake with no current and generally calm water. It warms up through July and August, but King County notes that lake water can stay cold enough early in the season to tire strong swimmers. The city staffs lifeguards at the swim area in summer; the schedule usually runs from late June to late August, noon to 7 p.m. Outside those dates and hours you swim unsupervised. Loaner life jackets in several sizes hang on a rack by the water through the summer and are free to use.

There is no entry or parking fee. Park hours are 7 a.m. to dusk from April through September and 7:30 a.m. to dusk from October through March, and the parking lot gates open at 8 a.m. and close 30 minutes after sunset. The beach is first come, first served; only the picnic shelter and the sports fields are reservable through the city.

Water quality is the main thing to check before a summer swim. King County samples the Pine Lake beach for fecal bacteria during the swim season and posts results, closures and temperatures on its Lake swimming beach bacteria and temperature page, where you can also sign up for closure alerts. The beach has been closed for high bacteria before, and the county advises staying out of the water for a day after heavy rain and watching for toxic algae blooms, which can show up late in the season. Gas motors are not allowed on the lake, which keeps boat traffic around the swim area light.

Beyond the beach, the park has a car-top launch for canoes, kayaks and float tubes, picnic shelters, barbecue grills, two play areas, climbing rocks, a basketball court, a baseball and lacrosse field, restrooms and short trails under tall firs and cedars. Washington Department of Fish and Wildlife stocks the lake with rainbow trout, and the fishing season runs from the fourth Saturday in April through October 31, so expect anglers on the dock in spring. The park was a private summer resort, later called French's LaPine or Pine Lake Resort, from the 1910s until King County bought it in the mid-1960s, and the city took it over when Sammamish incorporated in 1999.