Walnut Beach Park is a city park on the Lake Erie shore in the Harbor neighborhood of Ashtabula, Ohio, run by the City of Ashtabula's parks office. The park sits just west of the mouth of the Ashtabula River, and its long sand beach runs west from the harbor's west breakwall. Wikipedia's Ashtabula article counts it as one of the city's two public beaches, the other being Lake Shore Park across the harbor. People have been swimming here for more than a century; a bath house went up on this stretch of shore in 1919.

The park address is 1645 Walnut Boulevard. From downtown Ashtabula, head north on Lake Avenue toward the Harbor, then follow Walnut Boulevard down to the lake. Walnut Beach Drive loops into the park, and there is parking inside the park a short walk from the sand. The city lists no admission or parking fee for its parks, and the beach is open to anyone, so a day here costs nothing. Visit Ashtabula County lists the park as open year-round. Restrooms are seasonal and may only be open during peak beach hours.

The swim area is the open sandy beach in front of the pavilions and concession stand. The bottom is sand, and the lake here is open water with wind-driven waves rather than a sheltered cove, so conditions change quickly. Lake Erie is shallow and warms faster than the other Great Lakes, and by midsummer the water is usually comfortable for most swimmers, though it stays cold well into June. The city's parks page says lifeguards are on duty during summer daytime hours, with the exact hours posted at the beach. In past seasons the city has contracted with the Ashtabula County YMCA for guards, who worked 11 a.m. to 5 p.m. daily from Memorial Day to Labor Day, and buoys marked the guarded zone. Outside those hours and outside the summer season, nobody is watching the water.

Take the lake seriously here. Drownings have happened at Walnut Beach, and Beach Hazard Statements for rip currents are issued for the Ashtabula lakeshore when north winds build surf. Waves can also push swimmers into the rocks of the breakwall at the east end of the beach; the Star Beacon reported lifeguards pulling three boys away from those rocks in 2017. Stay inside the buoys, stay away from the breakwall, and skip swimming on days with a hazard statement or red flag. The Ohio Department of Health and the local health department sample the beach for E. coli through the summer, and contamination advisories are posted fairly often, especially after heavy rain. Check the Ohio BeachGuard site or the signs at the beach before you go in.

Away from the water, the park has a concession stand, restrooms, picnic pavilions, a playground and an inclusive playground, sand volleyball, a bocce court and a birdwatching trail through the vegetated dunes behind the beach. The shoreline is a known birding spot: Visit Ashtabula County reports 230 species recorded here, with shorebirds in late summer and big flights of loons, mergansers and gulls over the lake in November and December. Anglers and walkers use the breakwall, and the Ashtabula Harbor shops and the lift bridge on Bridge Street are a short drive east.