Blockade of fear memory reconsolidation has attracted attention as a therapeutic strategy for the treatment of PTSD. Here, we investigated the effects of delta-opioid receptor (DOP) agonists, KNT-127 and SNC80 on the reconsolidation of fear memory in mice. Male C57BL/6J mice (6-8 weeks old) were subjected to contextual fear conditioning test. On day 1, the mice were conditioned with 3 foot shocks. On day 2, DOP agonists were administered subcutaneously (s.c.) and microinjected into the basolateral amygdala (BLA), ventral hippocampus (vHPC), and prelimbic (PL) and infralimbic (IL) subregions of the medial prefrontal cortex in mice. On day 3, mice were re-exposed to the chamber for 2 min as a memory testing (test session). As a result, KNT-127 (3–10 mg/kg), but not SNC80 (1–10 mg/kg), significantly decreased the freezing rates of mice in the test session. In addition, KNT-127 (50 ng/mouse) when administered to the BLA, IL, and vHPC, but not the PL, significantly reduced the freezing response during the test session. It also tended to inhibit the phosphorylation of ERK1/2 only when administered in the amygdala. On the other hand, SNC-80 had no effect on either of them. These findings suggested that KNT-127, but not SNC80, produces inhibitory effects on the reconsolidation of fear memory via BLA, IL, and vHPC in mice.