Type 1 diabetes mellitus (T1DM) involves the destruction of pancreatic β-cells, requiring ongoing insulin therapy. A promising alternative for management is pancreatic islet transplantation, or the bioartificial pancreas. Here, we examine the primary implantation sites for the bioartificial pancreas, highlighting their anatomical, physical, and immunological characteristics in the context of T1DM treatment. Traditionally used for islet transplantation, the liver promotes metabolic efficiency due to portal drainage; however, it presents issues such as hypoxia and inflammatory responses. The omentum offers excellent vascularization but has limited capacity for subsequent transplants. The renal subcapsular space is advantageous when combined with kidney transplants; however, its use is limited due to low vascularization. The subcutaneous space is notable for its accessibility and lower invasiveness, although its poor vascularization poses significant challenges. These challenges can be mitigated with bioengineering strategies. The gastrointestinal submucosa provides easy access and good vascularization, which makes it a promising option for endoscopic approaches. Additionally, the intrapleural space, which remains underexplored, offers benefits such as increased oxygenation and reduced inflammatory response. Selecting the ideal site for bioartificial pancreas implantation should balance graft support, complication reduction, and surgical accessibility. Bioengineered devices and scaffolds can address the limitations of traditional sites and enhance T1DM management.