As the utilization of degradable polymer coatings increased, the accompanying trade-off between good degradability and high-efficiency antidiatom adhesion due to their hydrophobic nature remains unresolved. The study presents a new hydrophobic surface-fragmenting coating consisting of degradable hyperbranched polymers (hereafter denoted as h-LLA<i><sub>x</sub></i>) synthesized by reversible complexation-mediated copolymerization with isobornyl acrylate (IBOA) and divinyl-functional oligomeric poly(l-lactide) (OLLA-V<sub>2</sub>), both derived from biomass, that exhibited superior resistance (∼0 cell mm<sup>-2</sup>) to marine diatom <i>Navicula incerta</i> (<i>N. incerta</i>) attachment with higher OLLA content. The combined impact of the microscale hollow semisphere micelles that self-assembled degradable hyperbranched copolymers and hydrolysis-driven self-renewable surfaces following immersion in seawater may account for the remarkable resistance of h-LLA<i><sub>x</sub></i> coatings against <i>N. incerta</i>. Detailed investigations were conducted across multiple perspectives, from hydrolytic degradation to broad-spectrum antibacterial attachment to ecotoxicity assessment. The excellent features of high resistance to marine diatoms and bacterial attachment, degradability, and environmental friendliness make the as-prepared h-LLA<i><sub>x</sub></i> coatings widely sought after for antifouling coating applications.