Abstract The Earth’s ionosphere is part of the upper atmosphere that consists of plasma. Plasma at the equatorial ionosphere is basically produced by photo-ionization of the thin upper atmospheric gases by ultra-violet and shorter wavelength photons from the sun. The EIA is typical plasma dynamic processes of the equatorial ionosphere and characterized as the occurrence of a trough in the ionization concentration at the equator and crests from about 150 in magnetic latitude in each hemisphere. In this study the ionospheric electron density data is recorded from in situ measurement of SWARM satellite. Specifically, we studied seasonal and longitudinal variations of the EIA for the year of 2014. It is found that the maximum electron density near equatorial anomaly crest yield their maximum values during the equinox months and their minimum values during the June solstice months. During Equinoctial months there is insignificant longitudinal variation in the EIA structure and in June solstice the longitudinal variation of EIA structure is different for different months. The longitudinal variation in the structure of EIA is also significant in those months grouped under December solstice.