Underwater Rendering is an extension for Stylized Water, a Unity add-on that provides stylized water simulation for a wide range of applications. The extension adds support for underwater rendering and visual effects in oceans, lakes, and ponds, and has now been updated for compatibility with Stylized Water 3.
Both Stylized Water and the Underwater Rendering extension were created by technical environment artist Jonathan van Immerzeel, also known as Staggart Creations, who is known for several high-quality assets available on the Unity Asset Store. According to the developer, the extension underwent a lengthy development process during which it was completely rewritten to ensure compatibility with Unity 6, take advantage of the Render Graph system, and add support for mobile VR.
One of the key features of this extension is its approach to handling above and underwater camera states. Unlike many implementations that rely on camera switching or visual tricks to simulate these transitions, this extension uses a waterline lens effect. This allows cameras to be partially submerged, enabling a smooth and gradual transition between above-water and underwater views.
The extension also includes a robust set of features for creating immersive and visually rich underwater environments. These include realistic water caustics projected onto geometry, underwater fog that adapts to shallow and deep water colors, and accurate underwater shading. In addition, scene lighting is translated into the underwater fog, including sub-surface scattering, and it reacts to dynamic directional and ambient lighting.

The updated version brings additional improvements. A new particle effect controller allows effects such as sunshafts and ambient or movement-based bubbles to follow the camera underwater up to a specified depth. Internal reflections are also supported, rendering the underwater environment using screen space reflections or planar reflections.
Integration with transparent materials is now easier to achieve, as the render queue of the effect can be manually configured. Support for mobile hardware has been added, enabling the creation of underwater VR experiences. The update also includes other optimizations that improve performance and ease of use.
For more information, be sure to visit the product page on the Unity Asset Store. Please note that the Underwater Rendering extension requires the Stylized Water 3 add-on.