2026.2 FastTrack release containing data from the atmospheric network of ICOS Research Infrastructure for 40 stations and atmospheric composition at all available vertical levels at stations El Arenosillo, Birkenes, Cabauw, Gartow, Hegyhátsál, Helgoland, Hohenpeißenberg, Hyltemossa, Ispra, Izaña, Jungfraujoch, Jülich, Karlsruhe, Křešín u Pacova, La Réunion, Lampedusa, Lindenberg, Lutjewad, Monte Cimone, Norunda, OPE, Ochsenkopf, Pallas, Plateau Rosa, Puijo, Puy de Dôme, La Réunion, Ridge Hill, Saclay, SMEAR-II Hyytiälä, Station Nord, Schauinsland, Steinkimmen, Svartberget, Torfhaus, Trainou, Utö - Baltic Sea, Westerland, Weybourne, Zeppelin Observatory and Zugspitze. This collection contains the FastTrack (Level 1.5) quality controlled hourly averaged data for the mole fractions of CO2, CH4, N2O, CO and meteorological observations measured at the relevant vertical levels of the measurements stations as well as flask samples analysed for CO2, CH4, N2O, CO, H2, SF6, delta13C_CO2, deltaO18_CO2, O2/N2 and 14C for the period 1 April 2025-20 January 2026. All stations follow the ICOS Atmospheric Station specification V2.0 (https://doi.org/10.18160/GK28-2188) and are certified as ICOS atmospheric stations Class I or II. Data processing has been performed as described in Hazan et al., 2016 (doi:10.5194/amt-9-4719-2016).