The genus Potamonautes s.l. was revised by Cumberlidge and Daniels (2022) who reduced the number of species assissigned to this genus (which is now treated as Potamonautes s.s.). In that work, this revised genus was assigned to the tribe Potamonautini in the subfamily Potamonautinae in the revised family Potamonautidae. Potamonautes sidneyi was redescribed by Peer et al. (2017). A subsequent genetic study of this species (Daniels 2017) restricted the number of specimens included in it, reduced its geographical distribution, and made it necessary to do a reassessment.

Potamonautes sidneyi is known from South Africa and Eswatini. It is known from more than 30 locations across its known range and has an extent of occurrence (EOO) of  379,774 km² and an area of occupancy (AOO) of 1,540 km². Its habitat is possibly impacted by residential and industrial pollution, however, the species is suspected to have a stable population trend based on recent collections from new localities made in the past five years coupled with a strong representation in museum collections dating back to over 100 years. Despite this, there is no direct information on the number of mature individuals, or population fluctuations. Similarly, there is little information on trends in habitat quality, and hence monitoring is needed to detect if the species are impacted significantly by pollution. This species is assessed as Least Concern.

Potamonautes sidneyi, as currently conceived, is known from South Africa and Eswatini and occurs in the Limpopo, Mpumalanga, North-West, Gauteng, Free-State, and KwaZulu-Natal Provinces of South Africa. The most northern locality for this species is Thohoyandou, in Limpopo Province, and the southernmost locality is in the coastal area of Port Shepstone, in KwaZula-Natal Province. Subpopulations tentatively identified as belonging to this species that occur near Mount Fletcher and Rhodes in the Eastern Cape Province and in Lesotho need further investigation because they might belong to a different species.

The species is known from many observations and specimen records across its range, including a number of recent observations. Based on this, the assumption is made that the species is still abundant where it occurs, and that the population trend is stable. However, no population monitoring has been conducted to date.

This large-bodied species is found in major rivers, small pristine mountain streams, reservoirs behind dams, and in lakes, and swamps. Potamonautes sidneyi commonly shelters in burrows dug into the side of muddy river banks or under large boulders in rivers with boulder-strewn or sediment bottoms. Crabs leave their shelters to feed, usually at night. This species is tolerant of moderate to high levels of organic pollution. In KwaZulu-Natal this species is typically found in the slower-flowing middle and lower reaches of rivers, and has not been recorded from the upper reaches and faster flowing tributaries of the Mzimkulu, Mzimvubu and Mkomasi Rivers. However, there are reports of P. sidneyi from the faster-flowing streams and upper tributaries of the Tugela and Mgeni Rivers draining the Drakensberg Mountains and their foothills. The presence of P. sidneyi in the upper drainages may have been assisted by impoundments such as the Woodstock, Kilburn, Driel, and Spionkop Dams in the Tugela River system and the Albert Falls Dam and Midmar Dam in the Mgeni River system (Gouws and Stewart 2001).

The species may be impacted by habitat loss and degradation due to human settlement expansion and industrial activities, if they are close to its habitat in the main rivers and tributaries. However, there are no significant population declines that have been noted, but the species should be monitored to assess the level of threat from habitat degradation caused by pollution from residential and industrial activities close to the rivers where it is found.