im going on vacation soon and i wanna go scuba diving but i wanna know if i need anything like a license. Or can i just do it?

No, you do not have to have a license to go scuba diving. However, you must have passed a scuba certification course and have your certification to rent equipment or get pressurized air in your tanks.

There are small tourist companies that will, for a fee, take you diving while providing you with equipment. They give you some very limited lessons and, of course, your diving experience is also very limited.

So, basically, without that certification you don’t have the freedom that a licensed diver has.