TCS “Geoelectromagnetic Observations” is responsible for the provision of data about the geomagnetic field between the Earth’s core and space. Magnetic observations provide data to study Earth’s external and internal processes. For this purpose, high sampling rates and resolution and a high instrument stability are required. Data from long-term observatories and short-term campaign measurements will be provided by the TCS. Global and regional magnetic field models will be provided by EGMODA (the European Geomagnetic Model and Data Archive) service. ESGI (the European Service of Geomagnetic Indices) will provide data and products related to geomagnetic activity. The EMTDAMO (the European Service of Magnetotelluric Data and Models) service was introduced for data that determine the electrical resistivity of the Earth’s sub-surface by measuring the response on natural time variations of the Earth's magnetic and electric fields. These data are collected from various sources as the basis for new and improved resistivity models of the Earth. The EMTDAMO service is the responsibility of EPOS Sweden.