Thank you! That idea of using a skydome so the sky is not black underwater worked perfectly. I recommend dragging in the SM_SkySphere mesh ( located in All > Engine > Content > EngineSky) into your own level, clearing the location to 0,0,0 and setting the scale to 10000 in x,y,z. If you want to use the material with the texture-based clouds, assign the material instance of M_Sky_Panning_Clouds2 (found in the same folder as above), or use a different one. If you do NOT want to use texture based clouds and just want your sky to be visible underwater, you can assign the M_SimpleSkyDome material (also in the same folder).