As coastal development becomes increasingly threatened by erosion, installation of armoring such as seawalls has been applied to protect property by permanently relocating the position of a dune. The physical impact of seawalls to beach ecosystems is relatively well-understood, but the impact to sea turtle nesting remains unclear. We investigated the impact using observations of loggerhead sea turtle nesting in Florida at a seaward wall over 7 years, and a more landward wall over 3 years. Nesting patterns indicated that passive erosion at seawalls likely caused fewer turtles to attempt to nest on armored beach when compared with unarmored beach. Nests placed in front of seawalls were more likely to be washed away in storms. Placement of walls further from the shoreline may only delay the impact to nesting turtles by a few years. Armoring is expected to multiply as sea levels rise and storms become more frequent; thus, the availability of appropriate nesting habitat for loggerhead sea turtles remains at risk.