Submerged Areas only appear in some Castlevania games in which the game is more exploration-based such as Castlevania II: Simon's Quest, Symphony of the Night and Order of Ecclesia. They're almost always connected to underground waterways and almost always an item is required to access these hard to reach areas, mostly due to the fact characters tend to float. In Alucard's case (being part vampire), he actually took damage from even touching water and thus needed several items before he could reach these areas. Oddly enough, air doesn't ever seem to be an issue with these stages.
Typical enemies are what you would expect underwater, mostly fish with the occasional water demon. Because they're naturally mostly unexplored areas, they tend to have excellent items, some of which even have sunken ships or ship remains as sub-areas.
- Castlevania III: Dracula's Curse - Sunken City of Poltergeists
- Castlevania Chronicles - The Underground Aqueduct
- Castlevania: Bloodlines - Atlantis Shrine
- Castlevania: Dracula X - Stage 5'
- Castlevania: Symphony of the Night - Underground Caverns, Reverse Caverns
- Castlevania: Harmony of Dissonance - Luminous Cavern
- Castlevania: Aria of Sorrow - Underground Reservoir
- Castlevania: Dawn of Sorrow - Subterranean Hell
- Castlevania: Portrait of Ruin - Forest of Doom
- Castlevania: Order of Ecclesia - Kalidus Channel, Somnus Reef
- Castlevania: Lords of Shadow - Mirror of Fate - Vertical Prison
- Castlevania: Lords of Shadow 2 - Forbidden Wing