This document specifies a set of principles and rules that algae producers, algae products industries, laboratories or other entities that collect algae and algae products samples must follow for the definition of their own sampling programs and sampling protocols. In the context of this document, algae are a functional group that include microalgae, macroalgae, cyanobacteria and Labyrinthulomycetes. As algae and their production processes are so diverse, this document does not define a specific sampling program and/or a specific sampling protocol. Instead, this document specifies the aspects that an organization shall consider when defining its own sampling program and protocol. This document describes when and how a representative sample shall be drawn. For guidance on sample preparation of dry and wet samples of micro- and macroalgae, and algae-based products, please refer to EN 17605:2022. This document is to be used for the collection of samples for lot characterization for commercial or legal/regulatory purposes. However, this document can also be used for any type of sampling of algae, including samples for quality control during production.