I live in a coastal city too, so I know exactly what you mean—that salty sea breeze can be brutal on anything metal. The short answer is: yes, an outdoor bench can hold up here without rusting in a year, but only if you choose the right materials.
Here’s the real deal: ordinary steel or iron benches will start showing rust spots within months in salt air. The moisture and salt particles are like tiny corrosion accelerators. But if you go for marine-grade aluminum (like 6061 or 6063 alloy), it naturally resists rust because aluminum forms a protective oxide layer. Stainless steel with high chromium content (like 316 grade) is also a top performer—it’s often called "marine grade" for a reason.
Another solid option is powder-coated steel, but you need to make sure the coating is thick and free of chips. Any scratch exposes bare metal, and the rust will creep in fast. Or you could go the non-metal route: outdoor-grade teak, HDPE recycled plastic, or cedar will never rust, though teak needs occasional oiling to maintain its golden look.
In my own experience, I have a powder-coated aluminum bench on my oceanfront deck—it’s been three years and zero rust. I just rinse it with fresh water once a month to remove salt residue. So yes, with the right bench and simple care, one year is absolutely no problem. Just don’t cheap out on bargain steel frames.