Triple point defines a situation of simultaneous equilibrium between the solid, the liquid and the gas phases.
For such an equilibrium, you simply write:
$$
\Delta S= \frac{\Delta H}{T}
$$
that rises from the fact that $\Delta G=0$.
Considering water molar ($m$) enthalpies for each phase transition at $273\,K$:
$$
\Delta H_{melting,m}=6.01\,kJ\,mol^{-1}
$$
$$
\Delta H_{vaporisation,m}=45.05\,kJ\,mol^{-1}
$$
$$
\Delta H_{sublimation,m}=51.06\,kJ\,mol^{-1}
$$
one realises that
- the entropy of the gas phase is higher than the entropy of the liquid phase.
- the entropy of the liquid phase is higher than the entropy of the solid phase
In this respect the triple point has no peculiar behaviour compared to other points where a two-phase equilibrium is established.