In the EU don't carry a lockblade or a knife with a pocket clip on your person if you are going to or thru an airport or public transport. Many European cops take a look at a pocket clip or a "flipper" opening lever or button and become suspicious that you are carrying an "automatic knife"--what we used to call a switchblade. You can miss your train or ride trying to explain what it really is, and if the cop decides he needs to consult a superior, you may well never see that knife again. I had Belgian cops confiscate a regular old Spyderco pocketknife because the hole in the blade made it a "one-hand opener"....
I don't want to do Ph.D-level research on European knife taboos. So I go by what my cop friends tell me about guns in the US: if you suspect that something will make a cop think he has probable cause to question/detain/search you or your vehicle, don't do it. And assume you are under camera surveillance in any public place--don't haul out your perfectly legal firearm from the trunk of your car just to show it off to somebody in a public place that isn't a range or adjacent to a legal hunting area. You may get to talk to the nice patrolman (and he may find other "questionable items" in the process of checking you out). All this goes double in Europe.
My strategy for years, since I lost my Spyderco in Brussels, is to buy a small pocket knife well before going over to Europe say, a Chinese Buck (or Bear and Sons if you are allergic to Chinese), get a little padded envelope at the PO or Staples, and mail it care "of yourself" to your first place of lodging. Take an identical envelope with you and mail the knife home before you go to the airport to return home. I've used this same strategy with a hunting knife--actually I've SENT one several times but each time decided to give the knife as a tip or gift to my host or somebody I hunted with. Europeans who are outdoorsmen like knives just as much as we do.
Or you can buy a great European blade when you get there and bring it home as a "working souvenir"! I am especially fond of Finnish knives and other Scandinavian hunting blades, just either ship them home ahead of your departure or put them in your checked luggage and declare them at US customs when you get home. I couldn't resist getting an Italian-made "Fox" folder in the especially nasty Sardinian style when I went there before COVID (not a knife to carry in the urban US, by the way.).
Have a great time--I especially love Croatia and Slovenia, but you will find hunters and shooters all over Europe if you look for them--it's a hard addiction to kill!
