The outer baily or ward (identify) of the castle served as both a protective barrier and a logistical space, housing stables, storerooms, and other facilities critical to sustaining the garrison during warfare. It includes a series of concentric curtain walls, connected by ramparts. The positioning of the towers at regular intervals allowed defenders to cover the entire perimeter with arrows or other projectiles. The space also facilitated movement between the inner and outer defenses, ensuring operational flexibility.

circa 1200 CE

The Hospitallers initiated a second major phase of construction at Krak des Chevaliers in the early 13th century CE, culminating in the addition of the outer fortifications, which gave the castle its present form. The outer curtain wall, standing 9 meters (30 feet) high, incorporated prominently projecting rounded towers—an innovation absent in the square-plan towers of the inner ward. This architectural feature, introduced at Château Gaillard in France by Richard the Lionheart between 1196 and 1198, was advanced for its time, as even contemporary Templar castles lacked such rounded designs. Notably, a southeast extension of the outer circuit, of inferior craftsmanship, was built later, though its exact date remains uncertain. Around the 1250s, a postern gate was integrated into the northern wall to enhance access.

The outer fortifications were equipped with arrow slits strategically distributed to minimize blind spots around the castle's perimeter. Above the walls, machicolations—structures enabling defenders to hurl projectiles down upon attackers—featured prominently. These machicolations were unusually compact, requiring defenders to crouch while using them, and exhibited a unique complexity surpassing similar features at Saône or Margat. Interestingly, they bore striking similarities to contemporary Islamic military architecture, such as the Citadel of Aleppo, underscoring the cross-cultural exchange of defensive techniques between Muslim and Christian forces. Access to these defenses was provided by a chemin de verre (wall-walk), which facilitated movement along the walls. Historian Hugh Kennedy described the outer defenses as "the most elaborate and developed anywhere in the Latin East", praising the structure as a masterfully engineered "fighting machine".

Enhancements to the main entrance accompanied the construction of the outer walls. The primary gateway in the northeast was connected to the castle via a vaulted corridor that ascended the slope. This passage incorporated a hairpin turn midway, exemplifying a bent entrance—a defensive feature originating in Byzantine architecture. However, the bent entrance at Krak des Chevaliers was particularly sophisticated, extending 137 meters (450 feet) and equipped with murder holes, enabling defenders to rain projectiles on attackers below. Straight paths through the corridor led to the space between the inner and outer walls, necessitating attackers to navigate the full length of the passage to reach the inner ward. This complex entry system significantly fortified the castle's defenses against assault.