Built seascapes, defined here as ocean spaces shaped by the deliberate construction and management of permanent offshore installations, represent a shift from centuries of mostly transient maritime activities and resource extraction, ushering in a new era of intensified human interaction with the marine environment and its complexities. These built seascapes, exemplified by offshore wind farms and undersea cables, fundamentally redefine our relationship with the ocean, turning it from a perceived wilderness into a cultivated and actively managed space. This shift brings both unprecedented opportunities, including clean energy production, expanded sources of blue foods, new avenues for recreation, and economic development, but also a host of complex challenges related to their governance, security and sustainability.