Extracorporeal membrane oxygenation (ECMO) may be a life-saving intervention for patients with respiratory or cardiac failure or cardiac arrest. Storing wet-preprimed ECMO circuits can reduce the time to initiate ECMO, but safety concerns remain regarding contamination, plasticization, and oxygenator degradation. A scoping review of the literature was conducted using PubMed, EMBASE, and Cochrane Libraries from inception to March 2025. Eligible studies investigated wet-preprimed ECMO circuits for complications of wet-preprimed ECMO circuits. Thirty-two studies met the inclusion criteria. Twenty-three studies reported the risk of bacterial and plasticizer effects over time. Bacterial contamination occurred earlier during storage but once a sterile circuit had been established, the circuit remained sterile. Plasticizer migration was observed to peak after wet priming and decreased over time. Crystalloid priming reduced leaching compared with protein-based fluids, whereas coated tubing further minimized degradation. Oxygenator integrity decreased over time with crystalloid priming. Impairment of gas exchange and increasing transmembrane resistance with increasing storage time were seen. Wet-preprimed ECMO circuits can be safely stored for up to 30 days if sterility is maintained. Large research gaps exist, including priming fluid choice, plasticization migration risks, oxygenator integrity, and duration of safe storage beyond 30 days.