Spearfishing Dive Knife

Welcome to Spearfishing School Part 19 of our 80+ part series written for people new to spearfishing. This blog is free for my readers and so is access to Spearfishing School during the beta stage. If you learn something here, sign up for our email list and share this page with someone that is looking to learn about spearfishing. It is a free way to say thanks.

Choosing a Dive Knife

Lets go over what the dive knife is used for in spearfishing. Contrary to popular belief, it is not held in your teeth to kill sharks. 🙂 Here is how I use my dive knife…


  • Rig Cutting – Your dive knife should be able to easily cut through any rigging you have on your speargun. This is why I prefer a knife with at least one serrated edge. If some how you wrap up in your shooting line you need a knife that can make quick fork of it.
  • Pith, Brain, Kill – These all mean the same thing. After a fish is shot it has to be killed. The dive knife is used to poke the brain or brain stem. A fish should be brained to end the struggle before removing the spear. This will end the fish quickly, and stop the thrashing that could attract sharks. A pointed tip is what you want. As for length, however long you think the blade should be to penetrate the skull and get to the brain of the fish  you are hunting.  My 4 inch pointed blade has no problem killing large Yellowtail. So leave the Rambo knives at home.

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Go to Part 20 – coming soon: How do I carry my fish?
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