1/2 Rial

Oman's half-rial denomination has historically been an awkward fixture in the series — low enough in face value to see genuine everyday use, high enough that the Central Bank has periodically reconsidered its place in the currency hierarchy. This 2020 issue moves the denomination onto Oberthur's OPTIKS substrate, a hybrid combining paper and polymer layers, which De La Rue had pioneered under a different trade name years earlier. Oberthur's version gives the note meaningful durability gains over cotton paper without committing fully to a transparent polymer window construction.

The TBB#237 reference places this among the later issues of the current Omani series. OPTIKS substrate notes from this period are still early enough in circulation that wear data is limited.