Although this genus was not as specialized as the eel-like pleurosaurs for aquatic life, various skeletal features support the idea that it had a semiaquatic lifestyle.

"Vadare" is the root of the English word "wade", which is the reason it was chosen for this genus, in reference to its perceived semiaquatic habits.

[1] The holotype of Vadasaurus herzogi is AMNH FARB 32768, a well-preserved but slightly flattened skeleton which is practically complete.

Each maxilla possesses about thirteen or fourteen acrodont teeth which are fused to the bone (as is typical for rhynchocephalians).

The postorbital, jugal, and squamosal bones on the side of the head curve upwards to form the bar between the upper and lower temporal fenestrae.

The squamosal also forms a large portion of the part of the skull behind the lower temporal fenestra, along with a thin and tall quadratojugal and a curved quadrate which probably supported a tympanic membrane (eardrum).

The palatines themselves are separated by the long and thin front parts of the pterygoids, which do not seem to possess teeth.

A jumble of thin bones in the middle part of the body are probably the remains of gastralia (belly ribs) and components of a cartilaginous sternum.

The phalangeal formula of the foot is 2-3-4-5-4, and each toe is long and ends in a curved claw, similar to those of the hand.

Vadasaurus herzogi is believed to be a close relative of the pleurosaurids according to a phylogenetic analysis published in its description.

Although the structure of Rhynchocephalia as a whole is changeable depending on the methodology used in the analysis, the Vadasaurus + Pleurosauridae clade seems to be one of the most well-supported parts of the whole order.

Although not technically a true pleurosaurid, Vadasaurus still possesses several features characteristic of the family, such as a long tail and nares, a wide metacarpal and metatarsal I, and limbs which are less well-ossified than those of other rhynchocephalians.

[2] Younginia capensis Prolacerta broomi Sophineta cracoviensis Pristidactylus Eichstaettisaurus schroederi Megachirella wachtleri Marmoretta oxoniensis Gephyrosaurus bridensis Diphydontosaurus avonis Planocephalosaurus robinsonae Rebbanasaurus jaini Godavarisaurus lateefi Theretairus antiquus Polysphenodon mulleri Opisthiamimus gregori Clevosaurus convallis Clevosaurus brasiliensis Clevosaurus hadroprodon Clevosaurus bairdi Clevosaurus hudsoni Clevosaurus cambrica Brachyrhinodon taylori Colobops noviportensis Sphenodon punctatus Cynosphenodon huizachalensis Sphenovipera jimmysjoyi Kawasphenodon expectatus Kawasphenodon peligrensis Pelecymala robustus Fraserosphenodon latidens Opisthias rarus Eilenodon robustus Sphenotitan leyesi Toxolophosaurus cloudi Priosphenodon avelasi Homoeosaurus maximiliani Kallimodon pulchellus Sigmala sigmala Vadasaurus herzogi Palaeopleurosaurus posidonae Pleurosaurus goldfussi Pleurosaurus ginsburgi Kallimodon cerinensis Sapheosaurus thiollierei Ankylosphenodon pachyostosus Oenosaurus muehlheimensis Vadasaurus is believed to have been at least partially aquatic, perhaps similar in lifestyle to the Galapagos marine iguana, Amblyrhynchus cristatus.