The disclosure provides a new cotton variety ST 5818GLT. The disclosure relates to seeds, plants, plant cells, plant tissue, harvested products and cotton lint as well as to hybrid cotton plants and seeds obtained by repeatedly crossing plants of variety ST 5818GLT with other plants. The disclosure also relates to plants of variety ST 5818GLT reproduced by vegetative methods, including but not limited to tissue culture of regenerable cells or tissue from cotton variety ST 5818GLT.