It has been suggested that a possible candidate for the present accelerated expansion of the Universe is “ phantom energy ” . The latter possesses an equation of state of the form \omega \equiv p / \rho < -1 , consequently violating the null energy condition . As this is the fundamental ingredient to sustain traversable wormholes , this cosmic fluid presents us with a natural scenario for the existence of these exotic geometries . Note , however , that the notion of phantom energy is that of a homogeneously distributed fluid . Nevertheless , it can be extended to inhomogeneous spherically symmetric spacetimes , and it is shown that traversable wormholes may be supported by phantom energy . Due to the fact of the accelerating Universe , macroscopic wormholes could naturally be grown from the submicroscopic constructions that originally pervaded the quantum foam . One could also imagine an advanced civilization mining the cosmic fluid for phantom energy necessary to construct and sustain a traversable wormhole . In this context , we investigate the physical properties and characteristics of traversable wormholes constructed using the equation of state p = \omega \rho , with \omega < -1 . We analyze specific wormhole geometries , considering asymptotically flat spacetimes and imposing an isotropic pressure . We also construct a thin shell around the interior wormhole solution , by imposing the phantom energy equation of state on the surface stresses . Using the “ volume integral quantifier ” we verify that it is theoretically possible to construct these geometries with vanishing amounts of averaged null energy condition violating phantom energy . Specific wormhole dimensions and the traversal velocity and time are also deduced from the traversability conditions for a particular wormhole geometry . These phantom energy traversable wormholes have far-reaching physical and cosmological implications . For instance , an advanced civilization may use these geometries to induce closed timelike curves , consequently violating causality .