The ocean is teeming with life. Hundreds of real-life species are there to be discovered, from seahorses to giant whales.
Are the local fish sick or agitated? Players can view their health status and then use a tranquilizer-like tool to zap the ones in need of rehab with healing energy.
The game also includes a storyline that players can follow as they choose. The plot involves Oceana, a woman who investigates the "Dragon's Song," which her father, a prominent ocean explorer, was searching for just before his death.
While at Nine Ball Island, players can become friends with a dolphin and teach it some new tricks. When ona dive, players can even bring along the dolphin, which players can hold onto for extra fast swimming.
For the first time in the series, friends who have broadband Internet access can connect and dive with one another via Nintendo Wi-Fi Connection, while using the Wii Speak microphone to converse.