Although Heliocopris japetus occupies a large range, it is localised to areas of deep sands, particularly in southern African savannas. However, as deep sands cover wide areas in this region and this species has been frequently recorded on cattle dung in farmland, it is not considered to be threatened. It is therefore classed as Least Concern.

This species was described from Sena in central Mozambique and shows a wide distribution in dry sandy savannas throughout southern and eastern Africa. In the northeast of its range in Kenya it occurs as a rarity and is known from only a few localities (Australian CSIRO 1970-1986, unpublished records). From here its range extends south to South Africa and west to Namibia (Davis et al. 2020). Within the intervening area records are also known from Botswana, Zimbabwe, Angola, Zambia and Tanzania. Unvalidated reports from Rwanda and some from the Democratic Republic of Congo may represent confusion with the related Heliocopris antenor (Davis et al. 2020), whose distribution is centred on the more humid, forested zone of west and central Africa. Tanzanian records also require validation (A. Davis pers. comm. 2023). It has been recorded between 11 and 1,757 m asl. (Davis et al. 2020).

This species occurs in relatively low population densities, probably by virtue of its very large body size.

Collection records for this very large-bodied, night-flying, tunnelling species are primarily from sand and rarely on sandy loam, sandy clay loam or clay, in areas where there is a mosaic of soil types (Australian CSIRO 1970-1986, unpublished records). It has been recorded in pasture, open shrub/woodland on cattle, buffalo, elephant or white rhinoceros dung as well as to light. In quantitative comparisons of six local habitat types near Tshwane / Pretoria, South Africa, this very large-bodied, night-flying, tunnelling species showed an extreme bias to occurrence on deep sand (total 26 individuals, with none on sandy clay loam) where it was primarily found in open woodland (total 14) and grassland (total 8), but also occurred in thickets (total 4) (Davis 1996). In Botswana it has been recorded, quantitively, from a variety of dung types with a bias towards pig and elephant dung compared to cattle and sheep dung. Elsewhere in southern Africa qualitative collection records appear to reflect bias to commonly encountered dung types such as cattle or elephant rather than any natural preference (Davis et al. 2020). It is flight active during the summer rainy season (November to May) (Davis et al. 2020).

This species occurs in savanna ecoregions that include deep sands within their borders. It has been widely collected in a block of southern African regions including Angolan Mopane woodlands (AT0702), Kalahari xeric savanna (AT1309), Zambezian and Mopane woodlands (AT0725), Kalahari Acacia-Baikiaea woodlands (AT0709), Zambezian Baikiaea woodlands (AT0726), Southern Africa bushveld (AT0717), and Southern Miombo woodlands (AT0719), but is uncommon elsewhere although there are two verified outlier records from Northern Acacia-Commiphora bushlands and thickets (AT0711) in Kenya, and several east coastal records including the Northern (AT0125) and Southern Zanzibar-Inhambane coastal forest mosaic (AT0128) (ecoregions based on Olson et al. 2001).

Across 137 Southern African localities mean annual rainfall is between 208 and 1,247 mm and mean annual temperature between 16.7 and 25.2 °C (Davis et al. 2020).

This species is unlikely to be under serious threat as it is widespread on deep sands where it is found equally in grassland and open woodland, and frequently on cattle dung (Australian CSIRO 1970-1986, unpublished records). Deep sands cover a wide area within its range (Davis et al. 2020).

Specimens of this species are offered for sale on the internet.

There are no species-specific conservation measures in place, and none are currently required as the species is unlikely to be threatened at present. However, in order to ensure accuracy in the assessment of its conservation status and extinction risk, it is recommended that records from tropical parts of Rwanda, the Democratic Republic of the Congo and Tanzania are verified, particularly as these may represent confusion with a close relative, Heliocopris antenor.