Diving, like swimming, is one of Lara's moves that has been in every single game since the original Tomb Raider. Most times when going underwater Lara has to hurry as her air supply is limited. On some occasions however Lara uses a breathing apparatus.
Tomb Raider Classic
In Tomb Raiders I, II, III, IV and V the controls were always the same. Only on one occasion, in the Tomb Raider Chronicles level Deepsea Dive does Lara wear a Extreme Depth Suit and does not have to worry about her air supply. At least until the suit gets damaged.
Tomb Raider Legend
Tomb Raider Underworld