Yes—you absolutely can, and it’s a fairly common weekend project. What most people call park bench legs are usually sold as bench ends, bench frames, or cast iron bench legs. They are the side supports that hold the seat slats, and you can find them new or used online, at hardware stores, or through outdoor furniture parts suppliers.
If you want the classic look, cast iron bench ends are widely available in styles ranging from simple to ornate. Search online marketplaces like Amazon, eBay, or Etsy, and check local architectural salvage yards. Aluminum is lighter and rust-resistant, while steel is strong but needs a good powder coat or paint. Used cast iron can be beautiful, but inspect it carefully for cracks before buying.
For the seat, choose weather-resistant wood such as cedar, teak, redwood, white oak, or pressure-treated pine. A typical bench runs about 4 to 6 feet long, with slats around 2 to 3 inches wide. Leave small gaps between the boards so rainwater can drain. Use stainless steel or galvanized hardware to prevent rust streaks, and pre-drill the holes to avoid splitting the wood. Sand and finish the boards with exterior oil, stain, or paint before you assemble everything.
Measure the bench ends before cutting the seat boards. Most replacement bench legs are designed for standard board lengths, but you can trim the boards to fit your space. Make sure the legs sit level; if the ground is soft, place pavers or pads under the feet.
Overall, buying just the legs or ends and building the seat yourself is a great DIY park bench project. When you build your own bench, you can choose the exact wood, finish, and size—and often save money compared with a ready-made bench.