When the player dives in deeper locations for longer periods of time, their diving level will increase. The effects of one's diving level increasing are that the player will be able to dive without using up as much air, tolerate diving in deeper parts of the ocean, and (in Endless Ocean: Blue World) unlock more equipment (which then becomes available for purchase from Nancy). The levelling system is featured in both games, but it seems to have more of an impact on gameplay in the second game (as the air supply in the first game doesn't usually run out for most players, as it is used up rather slowly whatever they player's diving level may be).