This species is generally associated with open, well-illuminated broad-leaved and mixed forests, bush and shrublands, meadows, gardens, vineyards, orchards, parks, lake shores and low riparian vegetation. Dark and dense forests are avoided. Subpopulations can tolerate periods of dryness and can be encountered in dry habitats (D. Cogălniceanu pers. comm. October 2008). Spawning and larval development takes place in stagnant waters such as lakes, ponds, swamps and reservoirs, and sometimes in ditches and puddles. The species has been reported from anthropogenic landscapes, including large cities. It sometimes occurs in sympatry with Hyla meridionalis (and produces infertile hybrids).

This is a widespread Palearctic species that is now considered to be endemic to Europe, from the Atlantic coast of France east to central parts of Poland, central Bulgaria, and Greece (throughout mainland Greece except the northeast, Euboea Island, Peloponnese, Crete, Ionian Islands, Thasos, Andros and possibly in other islands of Aegean Sea; Pafilis and Maragou 2020). This species is mostly absent from Scandinavia (except southern and eastern Denmark and extreme southern Sweden). The species had been introduced to the UK (the New Forest, southern England) but is now thought to be extinct there and is not mapped. This is a lowland species that has been recorded at a maximum altitude of 2,300 m asl (in Bulgaria), although this requires reconfirmation.

The previous taxonomic concept of this species occurred in Iberia (scattered subpopulations) and France, eastwards to western Russia and the Caucasian region, and southwards to the Balkans and Türkiye (except extreme eastern, southeastern parts). Following genetic analysis, Hyla molleri and H. orientalis have been elevated from subspecies level to distinct species (Stöck et al. 2008). Subpopulations from Spain and Portugal have now been allocated to H. molleri, and subpopulations from Türkiye, Romania and eastern Poland, Ukraine to southwestern Russia, northern Armenia, Iran (Gilan, Mazandaran and Golestan provinces), and Azerbaijan have been allocated to H. orientalis (Stöck et al. 2008).

Conservation Actions In-Place
This species is listed on Appendix II of the Berne Convention and is listed on Annex IV of the EU Natural Habitats Directive. The species is protected by national legislation in many countries, it is recorded in many national and sub-national Red Data books and lists and it is present in many protected areas. It is considered Endangered in Switzerland (Schmidt and Zumbach 2005), Vulnerable in Austria (Gollmann 2007) and Slovenia (Anonymous 2010), Near Threatened in France (UICN France et al. 2015), Czechia (Chobot and Nemec 2017) and Romania (Botnariuc and Tatole 2005). The species is Least Concern in Sweden (SLU Artdatabanken 2020).

In parts of this species' range, mitigation measures to reduce road kill have been established. The species benefits from pond creation programs in several areas of Central Europe. This is often a flagship species for numerous restoration programs. The species has been reintroduced to Latvia (Gaua National Park, Riga District) in 1987–1992 from Belarus and from captive bred individuals raised at Riga Zoo. In Sweden, a "restocking program" has successfully increased the population from 2,000 (1980) to 50,000 (2008) in about 900 breeding ponds and the species has been repopulated to its historic range.

There were 21 LIFE-projects, where the species is listed among conservation targets or results: https://webgate.ec.europa.eu/life/publicWebsite/search/get?basicSearchText=hyla+arborea

Research Needed
Taxonomic research is required to delineate its range in Bulgaria, as it is currently considered to be a complex with Hyla orientalis (Y. Kornilev pers. comm. October 2019).