A study has been carried out on various aspects of occurrence as well as vertical drift of F3 layer over the magnetic equatorial location of Thiruvananthapuram [8.5 0N; 77 0E; dip lat of 0.5 0N] in India for the period from 1990−2009 using ionosonde observations. Diurnally, F3 layer occurrence exhibits a double peak pattern with maximum occurrence in the pre-noon, followed by a broad peak in the post-noon hours. The F3 layer exhibits a seasonal pattern of occurrence which is prominent only during low solar activity periods. The solar cycle variability of F3 layer occurrence is brought out in the present study using data from solar cycle 22 and 23. Further it is clear from the present analysis that F3 layer occurrence is high during periods of lower geomagnetic activity with Ap less than 20. The present study brings out an important aspect that there is no significant difference in the occurrence percentage of pre-noon F3 layers during solar cycle 22 and 23, while the post-noon F3 layer occurrence increases during the deep solar minimum periods at the end of solar cycle 23. The role of Counter Electrojet and the ensuing thermosphere-ionosphere coupling processes are proposed to be the reason for the above stated features of occurrence. The seasonal as well as solar activity dependence of the vertical drift of F3 layers is also brought out. The influence of thermospheric winds in determining the drift velocity is revealed.