In Level-2 processing, the products output for a given pixel depend on whether the pixel was identified as cloud, water or land. Cloudy pixels are discarded, whereas both water and land pixels undergo specific processing (OLCI ocean or land processing). The main difference between Sentinel-3 and MERIS in this respect is the estimation of errors, which shall be provided with every product. Two kinds of products have to be distinguished: OL_2_WFR/OL_2_WRR for water parameters (acquired on full and reduced resolution respectively) and OL_2_LFR/OL_2_LRR for land parameters.

All OLCI Level-2 products are encapsulated in free-standing netCDF product files. These files are collected in a SAFE container along with any additional information required by the SAFE format. All fields are stored in byte, short or long integer variable arrays. Each variable has a number of additional variable attributes defining a longer descriptive version of the variable name and, where appropriate, units, an offset, scale factor, maximum and minimum valid values, and a fill value to be used in place of missing data.