That's an excellent and very important question for anyone living near the ocean! Salty, humid air is incredibly tough on outdoor materials, causing rapid rust and corrosion. For a coastal trash bin, the absolute best material is Marine-Grade 316 Stainless Steel.
Here’s why: Standard 304 stainless is good, but type 316 contains molybdenum, which gives it superior resistance to chloride corrosion (the main culprit in saltwater). It's the gold standard for marine hardware. While it's a higher initial investment, it will last for decades with minimal maintenance—just an occasional rinse with fresh water.
If stainless steel is beyond budget, your next best option is a high-quality, marine-grade polymer or plastic. Look for bins made from UV-stabilized, thick polyethylene specifically designed for coastal use. They won't rust, but ensure they are heavy-duty to withstand wind and won't become brittle from sun exposure.
Materials to Avoid: Avoid plain or powder-coated steel, as the salt will quickly breach the coating. Regular galvanized steel will also eventually corrode in a harsh salt spray environment.
So, for long-term value and durability by the sea, 316 stainless steel is your top-tier choice, with robust, coastal-rated plastics as a solid, rust-proof alternative.