Thelotornis capensis is found in southern Africa.

[2] Thelotornis capensis is slender and has a long tail.

The longest museum specimen is a male with a snout-to-vent length (SVL) of 106 cm (42 in), a tail 62 cm (24 in) long, and a combined total length of 168 cm (66 in).

[3] Nota bene: A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Thelotornis.

The subspecific name, oatesi, honors British naturalist Frank Oates.