You pull your knife out of its sheath after saltwater dives and spot it: a faint orange freckle near the serrations, or a rough patch along the spine. Nothing dramatic, but it wasn’t there last month. Rust like that is rarely a sign of a bad knife. It’s a sign of a knife that went back into its sheath wet.
Stainless steel isn’t rustproof, and a short, consistent routine after every dive is what keeps a dive knife clean, sharp, and ready. Here’s what that routine looks like.
A quick note on stainless steel grades
Dive knives come in different stainless grades, and some resist corrosion better than others. Popular grades like 420 hold an edge well but are more prone to rust, so they reward divers who stay on top of care. Our 304 vs. 420 stainless steel post covers the full comparison.
Your after-dive routine
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Rinse it in fresh water: Take the knife out of the sheath and rinse both thoroughly, ideally soaking them for a few minutes. Salt hides in the sheath as much as on the blade, so don’t skip it.
- Clean off grit: Use a soft brush or towel to clear sand and debris from the serrations and around the wire cutter notch. Trapped grit holds moisture against the steel.
- Dry completely: Wipe the blade with a clean cloth, then let the knife and sheath air dry fully before putting them together. Sealing a damp blade into a sheath is the most common way rust starts.
- Add a thin protective film: Once dry, wipe the blade with a very light coat of oil, such as a corrosion-inhibiting or silicone-based product, then wipe off the excess. The goal is a thin film, not a greasy blade.
- Store it dry and ventilated: Keep the knife somewhere dry, away from damp neoprene and sealed gear bags. Storing it out of the sheath between trips gives it the best chance of staying rust-free.
What to do if you find rust
Catch it early and it’s an easy fix. For light surface rust, make a paste of baking soda and water, rub it gently along the spot with a soft cloth or non-abrasive pad, then rinse, dry, and oil the blade again. Avoid steel wool or harsh abrasives, which scratch the surface and give rust more places to grab. If the rust is deep or pitting the metal, it’s time to replace the knife rather than rely on it for safety.
Don’t forget the sheath and straps
A quick-release sheath traps water and sand just like the blade does. Rinse it with the knife, flush out the locking mechanism, and check that it still releases smoothly. A sheath that sticks is as much a safety issue as a dull blade.
Matching the routine to your knife
Saekodive’s Edge Series and Noir both have stainless steel blades with a smooth edge, a serrated edge, and a built-in wire cutter, so the routine above applies to either one. The Edge Series comes in small and large sizes with a quick-release sheath and two rubber straps for hands-free carry. The Noir has a blade with black electro-plating for added saltwater durability. Either way, the few minutes you spend on care after each dive is what keeps the steel looking and working like new.
- Edge Series Dive Knife - Regular price from $47.95 USD
- Noir Dive Knife - Regular price $55.95 USD
A dive knife is a tool you hope to never use in an emergency, which is exactly why it should be in perfect shape when you need it. Build the rinse, dry, and oil habit now and your blade will stay sharp and rust-free for years of dives. Happy diving!