From publisher blurb:
Yo-ho, yo-ho; a pirate's life for me!
The High Seas Update takes place at a time when there are still holes in the map to be filled. These blank spaces are a canvas of adventure, realms of pure swashbuckling exploits, where buccaneers can raid unsuspecting merchants, explorers can struggle against epic sea monsters, and pirates can bury treasure far away from polite civilization.
Inside its pages, you'll find everything you need to construct your own pirate adventure: a slew of races, archetypes, and spells, a treasure trove of magic items, new pirate weapons and equipment, a host of magical diseases, and, perhaps most importantly, a veritable armada of ships. It includes a comprehensive, easy to pick up, and fun to play system of ship combat rules and a ton of pre-built example ships so the whole crew can get in on the action.
More than that, High Seas comes loaded with a sizable bestiary, with entries ranging from colossal sea serpents to the diminutive parrots. Following that is a full complement of human NPC stats to fill the ships, ports, and island colonies of your campaign world, so that every inch of your campaign can feel fully inhabited.