This dataset contains the complete expedition report, the expedition map as well as a list of stations and sampling types. The 2018 Expedition Report is a collection of all the participating research teams’ Cruise Reports assembled by the Chief Scientists at the end of Leg 1, Leg 2 and Leg 3 of the Amundsen Expedition carried. The 2018 Expedition Report is divided into two parts: Part I gives an overview of the expedition, shows the cruise track and the stations visited and provides a synopsis of operations conducted during each of the four legs. Part II contains the reports submitted by participating science teams or researchers, with details on the specific objectives of their project, the field operations conducted and methodology used, and in some cases, preliminary results. When results are presented, they show the data as they were submitted at the end of the legs in 2018. The data presented in this report are illustrative only and have not been quality checked, thus parties interested in the results should contact the project leader or the researchers who collected the data. The sections in Part II describing each project are organized with atmospheric, surface ocean and sea ice components first, followed by water column properties, which nclude the mooring programs, CTD-Rosette operations and physical properties, ocean optical properties and freshwater sources as well as a suite of chemical and biological parameters. The contaminants cycling in seawater is also treated. The last sections of the report cover benthos sampling, seabed mapping, sediments sampling and ROV operations. The four Appendices provide information about the location, date, time and type of sampling performed at each station visited by the ship, as well as a list of science participants onboard during each leg. The core oceanographic data generated by the CTD-Rosette operations, as well as meteorological information (AAVOS) and data collected using the Moving Vessel Profiler (MVP), the ship-mounted current meter (SM-ADCP) and the thermosalinograph (TSG) are available in the Polar Data Catalogue (PDC) at www.polardata.ca