This chapter focuses on the fibril forming collagens type I, II, III; collagen type V and the basement membrane collagen type IV, given either their abundance, relevance to regeneration processes and possibility to purify those collagens from marine organisms. Fishes are certainly the most investigated source for the extraction of collagen, gelatine and collagenous peptides. Collagen and derived products can be extracted from skin, scales, bones and cartilages. The chapter provides an overview, as complete as possible, of the collagens successfully extracted from marine organisms. Collagen extraction and purification methods, as well as the final yield, mostly depend on the species used as a source, the starting material (i.e. anatomical part) and also the age of the specimens. It is possible to roughly separate collagens into four different categories: acid soluble collagen, pepsin soluble collagen, salt soluble collagen and insoluble collagen.