[1] Thelotrema fijiense has a thallus that is either epiphloedal or hypophloedal, thin, and varies in colour from whitish grey to pale olive or brown around the ascomata (fruiting bodies).

[1] The ascomata of Thelotrema fijiense are roundish, measuring 0.2–0.4 mm in diameter, and appear either solitary or occasionally fused at the margins, with a semi-emergent to emergent, flattened-hemispherical shape.

The proper exciple becomes free, at least in part, and is hyaline (translucent) to pale yellowish internally, with a yellowish-brown marginal area that is amyloid at the base.

The ascospores are transversely septate with thick, smooth, non-halonate, and hyaline cell walls that turn brown at maturity.

Pycnidia have not been observed in this species, and high-performance thin-layer chromatography indicates the absence of any secondary substances (all spot tests are negative).