Piracy may have existed as long as people have been regularly travelling across the seas. For example, it was commonplace in the Mediterranean in the ancient world, and it was commonplace in the Mediterranean two-thousand years later in the 16th century. It ranged from 'state-sponsored' actions, to organised piracy by marginalised people, dedicated pirate captains to occasional pirates - opportunistic traders, hard-up fishermen, and many more.

So you might want to specify a place and time period - I'm assuming you're thinking mostly about the "golden age of piracy" from about 1650-1730, which is popularly associated with the Caribbean, but also covers quite a few other areas.