As interest and opportunity in deep-sea mineral extraction grows, the increased activity poses a new threat to the underwater cultural heritage (UCH) sites in New Zealand’s deep-sea environment. Currently this environment is largely unexplored in terms of professional maritime archaeological investigation and recording, however, there are some significant shipwrecks such as the SS Ventnor, RMS Niagara, and SS Port Kembla, that have been explored by technical divers. Sites like these are both fragile and historically valuable and as such, current protection measures and potential adverse effects arising from seabed mining need to be assessed in order to understand how to offer some protection to the valuable information that lies on and below the sea floor. This chapter examines the potential risks to UCH posed by offshore resource development and reviews New Zealand’s current legislative framework, including the Resource Management Act 1991, the Heritage New Zealand Pouhere Taonga Act 2014, and the Exclusive Economic Zone and Continental Shelf (Environmental Effects) Act 2012. It highlights the regulatory gaps in the protection of UCH beyond the 12 nautical mile limit and underscores the need for urgent policy reform. With maritime archaeology still emerging as a professional discipline in New Zealand, the chapter calls for increased investment in site surveys, regulatory expertise, and public education. It advocates for a precautionary and proactive approach to offshore development that prioritises the identification, documentation, and protection of UCH as a critical component of New Zealand’s maritime heritage.