The concept of a substance acting as a prodrug for an intended drug is not new and has been known and utilized with particular benefits within medicine for efficacy and patient safety. Prodrugs of psychoactive substances are also not particularly new but this has also extended to considerations of prodrugs of new psychoactive substances (NPS). The continuing evolution of NPS has been a constant forensic challenge. In some countries, this constant evolution has led to the introduction of various alternative methods of drug control. Whether for this reason or in the pursuit of user experimentation, prodrugs of NPS have been discussed, developed, and exploited, posing some distinct forensic challenges. This is especially the case within toxicological analysis of biological fluids and for some substances, also forensic chemical analysis, through inherent instability of the prodrug or metabolism in the body. Particular examples of NPS prodrugs include 1-propanoyl-LSD, 1-butanoyl-LSD, 1-acetyl-LSD, and 2C-B-AN. This is in addition to associated substances and medicines that may be used for an intended pharmacological effect. Various prodrugs for stimulant and hallucinogenic substances in particular have appeared in the literature and have been discussed within drug user forums and made available for purchase online. Presently, drug monitoring data from national and international systems indicate that prodrugs are not widely available or problematic. Nevertheless, it is important that there is sufficient awareness of the prodrug concept and potential impact and associated forensic implications, not just for chemical analysis but also for toxicological considerations when a substance has been used.