A Starfleet fleet of the Dominion War, elements of which joined the Fifth and Ninth Fleets under Captain Sisko for the attempt to retake Deep Space Nine.
The Second Fleet is one of the numbered fleets Starfleet fields against the Dominion. Like the Seventh and Tenth, it is known mainly from the war's first year, when the Federation was losing ground across the front.
In Favor the Bold, Sisko persuades Starfleet Command to let him strike at Terok Nor before the Dominion can clear the minefield blocking the wormhole. He gathers ships from the Second, Fifth and Ninth Fleets at Starbase 375, but has to leave before all of them arrive, sailing with about six hundred vessels.
In Sacrifice of Angels this force meets more than twelve hundred Dominion and Cardassian ships. It is badly mauled until a Klingon fleet arrives and the Defiant breaks through to the station.