Oceania adds a number of items into the game. First and foremost is underwater content. Included right now are Underwater Villages, which are comprised of glass bubbles containing chests, ocean-loving villagers, and Atlantium Depulsors (read ahead for more information):
Another big feature Oceania adds is an expansion to your marine transportation options.
Firstly, it adds two new types of boats: the Iron Boat and the Atlantium Boat:
Each of these boats is more durable than the wooden one, the Atlantium being the strongest. They will withstand unfortunate mishaps (see: collision with a plant) more forgivingly than a vanilla Wooden boat. They also move faster than the Wooden boat.
In addition to these boats, Oceania also adds Boats with Chests:
These share the same properties as the aforementioned boat upgrades as well as containing a chest slightly larger than those found in your house.
Last but not least in the transportation category, we present to you the submarine:
The submarine is the fastest, most versatile form of marine transportation. It is able to dive underwater while allowing the driver to still breathe (hopefully), and allows the driver to see more clearly underwater than if they were simply diving. Unfortunately, the engineers forgot to allow room for a chest while building the engine compartment and thus the submarine does not have a form of onboard storage. Those engineers were fired and the submarine is being redesigned with such features in mind.
The content does not end here, however. Oceania also adds a number of useful items and blocks to the game, such as the following.
Atlantium is a very strong but blunt form of metal derived from the Atlantite alloy. It is created by using immense pressure and heat to refine Atlantite down into its purest form. Atlantite can be found in the ocean floor, and looks something like this:
It and its refined counterpart can be used to craft a number of useful tools.
The Atlantium Depulsor is a machine that uses the power of Ender to create a pocket of air in a body of water. Place it down and put some ender pearls into it to activate it. It can hold up to 32 ender pearls and each one powers it for half a Minecraft day:
The Atlantite Trident is a very powerful weapon suited for the King of the Seas. It has a base melee damage of 9 – stronger than the mightiest Diamond Sword. It looks pretty sweet too.
The Atlantium Helmet is useful for those who wish to dive underwater but who aren’t skilled in piloting a submarine. It will allow you to see very clearly underwater as well as breathe slightly longer than without the helmet. Unfortunately it does not protect against rogue squid attacks.