We set forth the structural and magnetic properties of the frustrated spin-$5/2$ triangle lattice antiferromagnet ${\mathrm{Na}}_{3}\mathrm{Fe}{({\mathrm{PO}}_{4})}_{2}$ examined via x-ray diffraction, magnetization, heat capacity, and neutron diffraction measurements on the polycrystalline sample. No structural distortion was detected from the temperature-dependent x-ray diffraction down to 12.5 K, except a systematic lattice contraction. The magnetic susceptibility at high temperatures agrees well with the high-temperature series expansion for a spin-$5/2$ isotropic triangular lattice antiferromagnet with an average exchange coupling of $J/{k}_{\mathrm{B}}\ensuremath{\simeq}1.8$ K rather than a one-dimensional spin-$5/2$ chain model. This value of the exchange coupling is consistently reproduced by the saturation field of the pulse field magnetization data. It undergoes a magnetic long-range order at ${T}_{\mathrm{N}}\ensuremath{\simeq}10.4$ K. Neutron diffraction experiments elucidate a collinear antiferromagnetic ordering below ${T}_{\mathrm{N}}$ with the propagation vector $k=(1,0,0)$. An intermediate value of frustration ratio ($f\ensuremath{\simeq}3.6$) reflects moderate frustration in the compound which is corroborated by a reduced ordered magnetic moment of $\ensuremath{\sim}1.52{\ensuremath{\mu}}_{\mathrm{B}}$ at 1.6 K, compared to its classical value ($5{\ensuremath{\mu}}_{\mathrm{B}}$). Magnetic isotherms exhibit a change of slope envisaging a field induced spin-flop transition at ${H}_{\mathrm{SF}}\ensuremath{\simeq}3.2$ T. The magnetic field vs temperature phase diagram clearly unfold three distinct phase regimes, reminiscent of a frustrated magnet with in-plane ($XY$-type) anisotropy.