The Great Sea in Origami King itself doesn't have much to do, except to get to different Islands. It does however hide many treasures and collectibles. This Paper Mario The Origami King The Great Sea guide will help you across the Great Sea and find all the Collectibles.

Paper Mario The Origami King The Great Sea
To enter the area of the Great Sea, you need to talk to the Blue Sailor Toad. He will provide you with the boat, and set sail.

The next thing you need is a map to help you navigate through the vast area. Sail into the fog and learn about getting a Sea Chart from Capt. T. Ode.

Return to town once you have collected the sea chart. Go to the museum and a cutscene will begin. The game will cut to the dock and Ode will give you the Sea Chart.

Set sail again, this time, with a Submarine in tow. This submarine will allow you to go under water and get all the secrets hidden deep within the Great Sea.

After the cut scene, Ode will teach you how to read the Sea Chart and how to use the submarine.

As far as the map is concerned, your boat is red and areas will be mapped as they are visited.

Once you are done, Sail to Bonehead Island. Use the Sea Chart to help you navigate through the fog.

Collectibles and Items
The biggest task to accomplish is to get all the treasure boxes and other collectibles in the Great sea, without any clue to their location.

In the middle of D7, talk to Shy Guy on a small island and reclaim his wallet that has fallen in the sea. Give it back to get your reward.

Near the lower right corner of D6, you will spot 4 small rocks. In the middle of these 4, you can use your submarine to go down. Notice the brown rock, grab it to break it and reveal the treasure chest hidden in it. Pen the chest to get the Origami Workbench.

In the lower left corner of F6, near rocks, you'll find some squids holing a treasure chest. Grab it and open it to get Paper Macho Stone Spike collectible.

In G7, under the squid-like rock formation, another chest can be found containing Paper Macho Gooper Blooper collectible.

In E5, locate a circular rock formation in the top left. In the center of this circle, a chest can be found containing Paper Macho Mummy Goomba collectible.

A Shy Guy can be found at the exact top right corner of A7. talk to him and go down in the submarine to get the Canned Heart. Now all you need is a can opener.

Along the left border of B5, another circular rock formation can be spotted. In the center of the formation is a chest containing gold coins.

In the lower left side of B3, a chest can be found containing Training Mannequin collectible.
Along the right border of C3, another Shy Guy can be found in between the rocks in that area. Talk to him and use your submarine to get a Big Shell under the sea.

On the right border of D3, near the rocks, a chest can be found containing the Healing Heart collectible.

Near the top left corner of D6, you will spot shadows of a school of fish swimming around. Get near them and then as they swim away follow them. When they reach the treasure, they will start to swim in a circle. Drop the submarine in the center of the circle. For this one, a chest can be found containing gold coins.

Near the left border of G3, a chest can be found containing the DJ Booth collectible.
A third circular rock formation in G1 near the lower left corner can be found. In the center of the formation, a chest can be found containing gold coins.

Another school of fish can be found among the rocks in E2. Follow them to find a chest containing gold coins.

Near the rocks along the left border of D2, a chest can be found held by squids. Get the chest containing the Spade Island Barrel collectible.

In A2, three tall rocks can be found. In the center of these three, a chest can be found containing gold coins. The chest is hidden behind the fishes swimming there.

In A1, near the bottom right corner, a chest can be found containing King Shroomses's Coffin collectible