The entrance into the sanctuary is through an entrance building (propylon), which was built entirely of marble by Idrieus (351- 344 BC). This is the South Propylon, which is 10.53 meters wide and 11.45 meters deep. It had two 5.4-meter-high Ionic columns on each front between the side walls. In the centre of the building was a cross-wall with three doorways.

South Propylon from the north-west.

Restored front of South Propylon.

(K. Jeppesen 1955)

    The columns on the fronts carried an Ionic entablature consisting of architrave, dentil and geison. The architrave towards the south was inscribed with the name of Idrieus as dedicator. No column capital is preserved but an anta capital can be seen inside the building.

To the left of the steps leading up from the south to the propylon floor is a block of marble from the south-eastern anta with an inscribed letter (dated 203 BC) from Zeuxis, minister of king Antiochos III, ordering the army to behave well at the shrine; it was not permitted to take up quarters at Labraunda, nor to gather flocks and herds in the gate-houses, or elsewhere.