Techs are the third playable faction. They enable a player to go underwater to build cities there. Techs are the sole faction that can build underwater, although they require terrestrial housing. Examples of Tech Buildings are the Laboratory and the Academy. The Techs work for S.A.A.T. The Techs' leader is F.A.T.H.E.R., their powerful AI.
Both Ecos and Tycoons can gain access to Tech buildings by paying 10,000 credits when the player achieves tycoon or eco engineers (tier 3), or you can change the game settings before the game to have both factions + the techs.