Surfacing or broaching.
A submarine is a ship that can travel underwater.
The process of a submarine to move from the surface of the ocean to a position underneath the surface is called a dive. This is accomplished by allowing water to fill the tanks of the submarine, the heavy water pressure now inside the vessel now will force it to sink below the surface, thus a "dive".
The Naval term for a submarine's initial rise above the surface of the water is called "broaching", e.g., a submarine has broached the surface. It takes more effort to fully surface a boat to where it's buoyant enough to stay on the surface. Broaching can be done intentionally or unintentionally by nature. If a boat is at periscope depth (about 65' for most boats), and sea swells are large, a big enough wave can suck a boat right to the surface without warning.
The is called "lava", before it comes out on the surface it is called "magma".
Royal Navy submarine
After you find the submarine you use dive up to the surface.
A submarine is kept at, or close to, surface air pressure.
Below the surface............
When a floating submarine submerges, it deliberately goes beneath the surface - which it is designed to do
A submarine is a sea-going vessel, both on the surface and under the water.
Enemy surface ships are the main target of submarine warfare
It is called a vent.