Ionospheric irregularities were small-scale fluctuations or disturbances in the ionosphere, the part of the Earth's atmosphere that is ionized by solar radiation. These irregularities can affect radio wave propagation and satellite communications, often leading to signal degradation or loss. They are typically caused by factors like solar activity, geomagnetic storms, and atmospheric conditions. They cause random and rapid fluctuations in the intensity and phase of the received signal. This study describes the longitudinal variations of equatorial ionospheric irregularities during solar maximum in different longitudinal sectors from January to December 2013. We used GPS data of TEC for the year 2013 from stations in EAST AFRICA in BDMT (11. 6 0 N, 37.6 0 E), WEST AFRICA in CGGN (10.1 0 N,9.1 0 E), SOUTH AMERICA in VERA (10.8 N,84. 7 0 E) and INDIAN in PBR2(11.6 0 N,92.7 0 E). The rate of change of the TEC index (ROTI) was calculated to determine the state of the ionosphere. Our result showed that the diurnal variation of ROTI values occurred at night or after sunset from 18:00 LT to 06:00 LT. For stations BDMT and PBR2, VERA, and CGGN, the maximum monthly ROTI values were observed in April, July, and September, respectively. Seasonal maximum values of ROTI for these stations were observed during the March equinox, June solstice, and September equinox, respectively. From the study, we conclude that the result of ionospheric irregularities varies according to the longitudinal position of the observation station. Therefore, the time of the maximum/minimum ionospheric irregularity values varies diurnally, monthly, and seasonally depending on longitude. 0