CMDs of the four different galaxy regions identified in the main body of I Zw 18 (see Fig. 1) and for which we independently recovered the SFH using SFERA 2.0. Region 1 (R1) and region 2 (R2) are the two innermost SF regions, in the northwest and southeastern part of I Zw 18’s main body respectively. Region 3 (R3) and region 4 (R4) are the middle and outermost selections of the main body. Over-plotted on the CMDs and color-coded according to their age (see legend on the top-right corner) are some PARSEC-COLIBRI isochrones with [Fe/H] = −1.60. The darker shading obscures the region of the CMD that falls below our established 50% completeness level.