Deep sea mining (DSM) has the potential to impact underwater cultural heritage, both tangible and intangible. The BBNJ Agreement will have implications for any underwater cultural heritage affected by DSM activities under its focus on marine biodiversity, its provisions on EIAs including strategic environmental assessments (SEAs) and ABMTs, and for its specific recognition of cultural values. It also has implications for the positions of BBNJ Parties when participating in the International Seabed Authority (ISA). Traditional knowledge is mainstreamed throughout the BBNJ Agreement, as is consultation and transparency. Protecting underwater cultural heritage under the BBNJ Agreement is likely to involve extensive consultation with both the ISA and UNESCO. Cultural matters as well as traditional knowledge are specifically included in both the ABMT and the EIA parts of the Agreement, but are also likely to arise in other contexts, including capacity building and the transfer of marine technology. Once BBNJ enters into force, international cooperation provisions including with respect to the ISA where activities in the Area are concerned and UNESCO when underwater cultural heritage or intangible cultural heritage is concerned will be important in resolving issues.