Here, we report superconducting Mg11B2 wires made by using the internal Mg diffusion technique with isotopic amorphous nano boron (11B) as the precursor material. We show the influence of annealing temperature and isostatic pressure of 0.1 MPa and 1.1 GPa on Mg diffusion into 11B layer, microstructure of superconducting filament, critical current density (Jc) at 20 K and 25 K, critical temperature (Tc) and irreversible magnetic induction (Birr) in mono (single-core) - and multi-filament Mg11B2 wires. Our research shows that thermal treatment at 700 °C and 0.1 MPa for 60 min yields a superconducting phase with low Tc, Birr and Jc in single-core Mg11B2 wire. A higher annealing temperature (740 °C and 0.1 MPa for 60 min) significantly accelerates the diffusion of Mg into the 11B layer and increases the Tc, Birr and Jc. However, the distribution of Mg in 11B layer is very heterogeneous (places with high and low Mg concentration). This leads to heterogeneity in the superconducting materia