Transhumanism is an unsettling prospect for proponents of a natural law ethic. The goal of transhumanism is to fundamentally alter our human nature, while the natural law tradition relies on this nature for producing normative claims. The tension seems clear. But beyond the need to explore this underdeveloped relationship, it may be that natural law provides precisely the sort of ethical framework—a framework centered on human nature—for best evaluating transhumanism and bioenhancement technologies. Building on the work of Jason T. Eberl and Brian Patrick Green, I articulate how a Thomistic theory of natural law can guide us in a brave new world. Along the way, I note ways in which both Eberl and Green are too limiting in their interpretations of natural law, but in offering these critiques, I hope to bring out how natural law proves an invaluable guide for navigating life in creation—even a creation that has been tampered with.