There are three subspecies: Coronella austriaca austriaca is present over most of the species range; C. a. fitzingeri (Bonaparte, 1840) inhabits the southern part of the Italian Peninsula and the island Sicily; C. a. acutirostris Malkus, 1995, has been erected for the populations of the north-western Iberian Peninsula. The results of an mtDNA phylogeographic study of this species suggests that, despite the lack of consistent morphological variation across the range, the current taxonomy "does not reflect the rich genetic diversity, deep divergences, and overall evolutionary history" of smooth snakes, and highlights the need for a full taxonomic revision of this species complex (Jablonski et al. 2019).

Simotes semicinctus was described in the 19th Century from a specimen with the locality data "probably Borneo", and was never subsequently rediscovered (Tillack et al. 2008). Wallach and Bauer (1996), accepting this uncertain locality data, referred this species to the Southeast Asian genus Oligodon. Tillack et al. (2008), however, examined this specimen in detail and concluded that it is not referable to Oligodon. Considering the locality data unreliable and comparing the specimen with snakes globally, these authors reached the unexpected conclusion that S. semicinctus is a junior synonym of Coronella austriaca. The Borneo locality must consequently be considered in error, as has been found with other specimens from the same collection (Tillack et al. 2008).

European regional assessment: Least Concern (LC)
EU 27 regional assessment: Least Concern (LC)

The smooth snake is assessed as Least Concern for Europe and for the EU27 Member States in view of its very wide European distribution and presumed large population in both Europe and the EU 27. Although it is declining in parts of its range, and very rare in some areas, these appear mainly to be comparatively localised and commonly at range margins (e.g. in Spain, Sweden).

In Europe, this species ranges from southern Scandinavia (Norway and Sweden, where it is rare and its population extremely fragmented) and the Baltic region, southwards as scattered subpopulations through western, central and eastern Europe (excluding most of mainland Denmark, parts of southwestern France, and much of southern Iberia) as far east as central and southern European Russia, and south to Turkish Thrace. It is also found in southern England and the Italian islands of Elba and Sicily. In Russia it ranges north to approximately 57 °N in the west, and almost to 58°N in the middle Urals, corresponding almost exactly to the area where the mean July isotherm is 18 °C (Antonyuk 2013). It is found from sea level up to 2,750 m asl (Speybroeck et al. 2016 state 2,700 m).

Outside Europe it ranges into northern Türkiye (much of Anatolia, with some isolated southern subpopulations), the Caucasus region, northern Iran (Central Province) and western Kazakhstan.

This species can be generally common in southern parts of its European range, but it is rare, with fragmented subpopulations in many northern parts of its range (including the northern portion of its European Russian range - Antipov et al. 2021). It is moderately common in Germany but considered to be declining across the country (and particularly in the north) (Rote-Liste-Gremium Amphibien und Reptilien 2020). The species can be hard to detect and subpopulations may be overlooked (B. Schmidt pers. comm.). It is rare everywhere in southern Sweden but especially on the Baltic island of Åland, where genetic evidence suggests the subpopulation is "critically small" (Galarza et al. 2014). In Switzerland, it is still relatively abundant in the Alps but there is an ongoing decline in the lowlands, mainly due to agricultural intensification (Swiss red list: Monney & Meyer, 2005b). It is also extremely rare in the isolated populations of the southern Iberian Peninsula (J.M Pleguezuelos pers. comm. October 2008). In one Spanish survey, only five individuals were recorded during more than 3,500 hours of targeted fieldwork (Santos et al. 2009). A subsequent study modelling rates of decline based on citizen science data collected between 1980 and 2017 (Spain) and 1980 and 2018 (Languedoc, France) found that the population had declined by 59.7% in Spain and 48.2% in southern France over this period, corresponding to declines of 23.58% and 18.51% respectively over a presumed three-generation period of 15 years (Santos et al. 2022). The evaluation conducted for the last Swiss Red List (OFEV & info fauna, 2023) evaluated a 41.5% reduction of occurrence in random square kilometers over 3 generations. There is some evidence of a decline in European Russia (Ananjeva et al. 1998), where it occurs at extremely low densities and has a fragmented subpopulation (K. Milto pers. comm. 2016).

The species is found in moorland, rocky coastlines, open woodland (deciduous, coniferous and mixed) and scrubland, hedgerows, woodland edges, heathland, sandy coastal sites, rocky areas, screes, subalpine and open areas with sparse vegetation. Although the species swims well, it avoids damp places. On the southern Iberian Peninsula and in Greece it is largely restricted to upland or montane areas. Animals shelter in rodent and lizard burrows, beneath stones or logs, or within cracks in rocks. It is believed that an area of suitable habitat considerably greater than 100 ha is required for the long-term persistence of subpopulations (Goddard 1981, Völkl et al. 2017). Between two and 19 (Speybroeck et al. 2016 state up to 9) fully formed young (3.9 on average) are born at the end of August - October (Speybroeck et al. 2016). It has an assumed generation length of five years (Santos et al. 2022), inferred by these authors to be a year later than age at maturity. The period of activity lasts from February - November depending on latitude (Speybroeck et al. 2016).

It is threatened in parts of its range by the intensification of agricultural practices, afforestation of open areas (e.g. in Belgium) and fires in woodland or scrubland. Many subpopulations are vulnerable because of their fragmented nature, and through overgrowth of the species' preferred open habitats (for instance, in abandoned traditional farmland). In Germany, declines have been driven by large-scale clearance of moorland and heathland in the country's north and vineyards in the south, and the small area of remnant habitat is insufficient to support the long-term persistence of remnant subpopulations in many areas (Rote-Liste-Gremium Amphibien und Reptilien 2020). As the species is hard to detect, it can be missed in environmental impact assessments with the result that development may inadvertently destroy subpopulations (Rote-Liste-Gremium Amphibien und Reptilien 2020). Subpopulations from the southern Iberian Peninsula (Sierra Nevada) could be threatened by climate change and displacement by more competitive Mediterranean species (J.M. Pleguezuelos pers. comm. October 2008). Intrinsic threats for southern populations include poor recruitment capacity, extremely low density, isolation of populations, and global climate warming (for mountain populations) (J.M. Pleguezuelos pers. comm. October 2008). While it is not collected, the species is sometimes persecuted through confusion with vipers. The species appears to have strongly declined in Belgium, a decline that may be linked to a rapid expansion of wild boar populations in this country (Graitson et al. 2018). Some management (grazing for instance) have a strong impact on the species density (Graitson et al. 2020).

There is no use or trade in this species.

This species is listed on Annex II of the Bern Convention, and on Annex IV of the European Union Habitat and Species Directive. It is protected by national legislation in parts of its range in most western European states. The species is present in a number of European protected areas. The population should be monitored in parts of its range, as it is under heavy local pressure in many areas. Habitat restoration through the installation of hibernacula (using stone or deadwood) and drystone walls in areas is recommended in areas of Germany with suitable vegetation structure, bog restoration, and the creation and maintenance of both natural and artificial (such as escarpments, power lines, or railways) habitat corridors in ways that account for the needs of this snake (Rote-Liste-Gremium Amphibien und Reptilien 2020).

It is included in the national Red Data Books of a number of counties. This species is currently categorized as Vulnerable in Poland (B. Borczyk pers. comm.) and Ukraine (Kotenko 2006). This species was categorized as Vulnerable in Switzerland in the previous Red List (Monney and Meyer 2005) is now considered as Endangered (OFEV & info fauna, 2023). It is listed 'Threatened with Extinction' in the German national Red List (Rote-Liste-Gremium Amphibien und Reptilien 2020). It is listed as locally Least Concern in Türkiye.

In many regions of Russia this species is listed in regional Red Data Books with the status of a "rare species", for which low abundance is a biological norm.