A multisiphon passive cooling system includes a heat exchanger thermally connected to a heat-generating component located within an enclosure, a distribution manifold located below the heat exchanger, a condensing unit located external to the enclosure and above the heat exchanger, and a first conduit thermally connected to the heat exchanger. The first conduit is fluidly connected to the distribution manifold and the condensing unit. The cooling system also includes a second conduit fluidly connected to the condensing unit and the distribution manifold, a liquid bridge fluidly connected to the first conduit and the second conduit or the distribution manifold, and a two-phase cooling medium that circulates through a loop defined by the first conduit, the liquid bridge, the condensing unit, the second conduit, the heat exchanger, and the distribution manifold. As such, the liquid bridge transfers the cooling medium in a liquid state from the first conduit to the second conduit or the distribution manifold.