The historical relationship between humans and marine mammals is ancient and complex. Beyond hunting for food, a whole set of links exist between human and non-human coastal communities. Marine mammals are indeed fully integrated into boreal cosmogonies and cosmologies, and sometimes directly included in ontogenies and ontologies. All of these strong links are part of a specific intangible cultural heritage (ICH). ICH is a new category of heritage recognized globally thanks to a dedicated UNESCO’s Convention (2003). Since this Convention on the preservation of ICH, a real international framework around this particular heritage has emerged. This framework has allowed the countries that have ratified it to initiate processes of inventory, then classification and preservation of this heritage. The ICH is a complex heritage, in essence plural, and above all, difficult to conserve, because it is living and not material. It differs in this respect from cultural and natural heritage, even if it maintains strong interrelations with these other heritage categories. The relationship between humans and marine mammals is thus part of different categories of ICH. Several coastal communities have engaged in processes of inventorying this specific ICH, and some have gone as far as international classification by UNESCO, such as the island of Kihnu (Estonia), which was able to reopen seal hunting thanks to this classification in the mid-2000s. The mobilization of the tools of this convention can be envisaged to allow the long-term preservation of this heritage. The case of Kihnu is highlighted, along with other examples and ways of preservation. Recognition by the Convention can also make it possible to extend certain actions beyond the 'simple' maintenance of the activity: popular education and transmissions, taking into account IPLC's knowledge, etc.