You planning on checking this or taking it through security? After my 3 trips to the Philippines all I can say is whatever the official rules are, they doesn't necessarily matter. (And even if a blade is small enough, if it has other tools, security usually isn't happy about that either.) If you're questioning this and don't really need it, why ask for the possible hassle?
When I travel I try to pick what to take based on what I really need on a trip. I try not to cart along along all the stuff I do at home, because I'm not at home. It all adds up. I do carry small round tipped scissors as I find them useful for many things, but they seem less likely to be a problem.
If you put it in your checked bag, then go directly to some dive resort, probably ok. If you will spend an overnight in some city, metal detectors at the entrances to hotels, malls, etc. seem not uncommon. (I don't know how they feel about pocketknives but we've had to check dive knives at the door of the Manila Marriott were we have stayed a couple times.)
