  We present magnetic susceptibility and electrical transport measurements of
the highly anisotropic compound LaSb$_2$ observing a very broad transition into
a clean, consistent with type-I, superconducting state with distinct features
of 2 dimensionality. Application of hydrostatic pressure induces a 2- to
3-dimensional crossover evidenced by a reduced anisotropy and transition width.
The superconducting transition appears phase fluctuation limited at ambient
pressure with fluctuations observed for temperatures greater than 8 times the
superconducting critical temperature.
