Abstract: Reinforced concrete arches are common structures in engineering and may be subjected to explosion loads during their service life. To investigate the influence of detonation location on the dynamic response and failure characteristics of submerged RC arches, two specimens were fabricated and underwater explosion tests were conducted. The tests were divided into two groups: vault explosion and lateral explosion. In each test, 6 g TNT charges were used, with the standoff distance of 10 cm from the arch surface (the initiation points were located directly above the arch, and at 45° on the side). Pressure and acceleration time histories at typical sections of the RC arch were recorded by sensors during the tests. A multi-medium dynamic coupling model, including air, water, explosive, and RC arch, was established based on the Arbitrary Lagrange-Euler (ALE) algorithm. The numerical model was verified through comparison with experimental results.. Based on the validated model, the dynamic response of RC arches under vault and lateral explosions was further analyzed. The results show that under the same explosive weight, the damage to the structure caused by lateral explosion is greater than that caused by top explosion, and the number of cracks increases. Under the top explosion, the structural deformation is relatively symmetrical, mainly concentrated in the arch vault and arch waist, while the lateral explosion causes asymmetric deformation in the horizontal and vertical directions. The response is most severe in the areas directly opposite the explosion source and the arch waist on the far side.