For VLF you can drag a very long antenna behind you, but most submarines just launch a buoy with a normal antenna to the surface and a fiber connection to allow them to stay below the surface.
I did notice the bit in the Wikipedia article where they mention the US station isn't used for submarine comms anymore. Thanks for the higher quality info.
How does existing submarine cable infrastructure carry communications to subs?
Low-frequency AC current in the shield, data picked up magnetically?