Two field experiments were conducted at the Ismailia Agricultural Research Center Station during the summers of 2021 and 2022 to study the effects of cyanobacterial inoculation (Anabaena oryzae and Nostoc mascarum) on peanut plant growth, yield, and certain soil biological activities under different nitrogen fertilisation ratios and conditions. There are three applications: soil drenching, cyanobacterial seed coating, and foliar spray with cyanobacterial strains.The findings demonstrated that cyanobacteria inoculation of peanut plants generally improved peanut plant growth, resulting in significantly higher peanut and grain yields than uninoculated treatments. When compared to other tested treatments and types of applications, N. mascarum + 75% (N) produced the highest peanut yield and plant characteristics, followed by A. oryzae + 75% (N) in soil drench application. Overall, cyanobacteria increased the amount of N, P, K, and Ca in peanut plants. Cyanobacteria inoculation improved soil fertility by increasing total bacterial and cyanobacterial count (CO2) evolution, and indole acetic acid contents in the peanut rhizosphere. In general, peanut growth in sandy soil conditions can benefit from cyanobacteria inoculation with 75% nitrogen amounts.