Devices and methods for providing an internal balloon sheath are disclosed. One device includes a sheath for insertion through an arteriotomy of a patient. The sheath comprises a tubular sheath body having a longitudinal axis, an open proximal end, an open distal end, an outer surface and an inner surface, the inner surface defining a lumen between the proximal and distal ends for passage of a catheter device. The sheath also comprises an inflatable balloon disposed within the lumen. The inflatable balloon is configured to occupy a longitudinal space in the lumen between the inner surface of the sheath body and the catheter device when the catheter device is disposed within the sheath and the balloon is inflated, and fluidically seal the lumen.
