Seems like they're using an optical cable to transmit the video feed back to the ship, then transmit back to the internet through satellite communication.
Congrats to around 110k people who are currently diving :D
Seems from the last few minutes like a Japanese studio discussion overlayed on top of a fixed poor-angle picture of three guys locked in a tiny space, with the occasional cut to a piece of machinery in the black doing nothing recognizable. Meh, pass.