Three samples of biobased poly(ethylene 2,5furandicarboxylate) (PEF) with various molecular weights (MWs) were synthesized. Their crystallization was studied by using differential scanning calorimetry (DSC), modulated temperature DSC (MDSC), wide-angle X-ray diffractometry (WAXD), and polarized light microscopy (PLM). The rates of isothermal crystallization from the melt decreased with increasing MW. One up to three melting endotherms were observed in DSC heating thermograms of samples crystallized isothermally. This behavior was interpreted in the context of recrystallization/reorganization phenomena. Recrystallization and multiple melting were associated with low stability samples crystallized at low crystallization temperatures (T c 's) and with low molecular weight. However, the multiple melting of PEF crystallized after self-nucleation was attributed to a dual morphology. As PEF crystallized slowly, its melt crystallization on cooling at 15 different slow rates ranging from 0.1 to 5.0 °C/min was studied, while the crystallization from the glass was investigated upon heating at 15 different rates from 0.25 to 10 °C/min. A large amount of the collected data was treated using various models. But most importantly, critical observations were made by combining all the available raw data and results from different techniques and methods, allowing for better understanding of the crystallization and melting of thermoplastics under various conditions. The limitations of the experimental techniques and data treatments were evaluated.