This study examines the relationship between the El Niño--Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) with Iran's precipitation patterns. Correlation analyses were conducted between ENSO indices (Nino1+2, Nino3, Nino3.4, and Nino4) and IOD phases, specifically the negative (NIOD) and positive phase (PIOD), using monthly and seasonal precipitation data from 91 synoptic stations across Iran from 1990 to 2018. On a monthly scale, the Kendall Tau correlation showed significant correlations at a 95% confidence level across most regions of Iran for all indices, except for the Nino3.4 index. Direct correlations up to 0.5 were noted with the Nino1+2 index and up to 0.3 with the Nino3 index, excluding the Caspian Sea coast. Inverse correlations of -0.3 with Nino4 and up to -0.5 with PIOD were found in all basins except the Caspian Sea. The results also indicated correlations up to 0.5 in many regions of Iran with the PIOD index. Seasonally, no significant correlations were observed between precipitation and the indices in winter, summer, and autumn. However, in spring, only the Nino1+2 and Nino4 indices showed significant correlations, with Nino1+2 ranging from 0.5 in the west to 0.3 in central and eastern Iran and Nino4 showing an inverse correlation up to -0.3. The Pearson correlation also demonstrated significant relationships between monthly precipitation and the indices, particularly for Nino1+2 and PIOD. Correlations up to 0.5 were observed across Iran, increasing to 0.7 in the Ghareh Ghowm basin. The PIOD index showed an inverse correlation, reaching -0.5 in the eastern and northeastern regions (Ghareh Ghowm basin). These findings highlight that the Nino1+2, Nino3, and NIOD indices positively correlate with Iran’s precipitation, while the Nino4 and PIOD indices show a negative correlation. Nino3.4 does not exhibit a significant relationship with precipitation in Iran. These insights are valuable for improving forecasting and water resource management.