There is a high demand for highly biobased photocurable coatings for a wide range of applications. In this work, a photocurable coating formulation is developed based on isobornyl acrylate (IBOA) and a biobased polyester diacrylate. Besides, a phosphorous‐containing biobased dimethacrylate resin having imine groups (VDDM) is synthesized. Different ratios of VDDM are added to the biobased base formulation. VDDM is characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopies. The formulations are coated on aluminum substrates and photocured under UV light. The biobased contents of the prepared networks are in the range of ≈68–79%. Coatings display a good adhesion on the aluminum substrates. The incorporation of VDDM into the formulations slightly increases the glass transition temperature values. Moreover, VDDM enhances the hydrophilicity of the coatings. VDDM‐free coatings are found to be resistant to degradation under basic and acidic media, but the presence of imine bonds in VDDM leads to the partial degradation of the prepared networks under acidic aqueous conditions. Finally, it is demonstrated that the coatings prepared herein are resistant to corrosion. The prepared highly biobased networks in this study have the potential to be used as photocurable coil coatings.