Caught unaware or not yet reacted: no DEX to AC, no attacks of opportunity.
A flat-footed character has not yet reacted -- ambushed before they could
bring their guard up, or still mid-turn when the shooting started. They lose
their Dexterity bonus to AC against every attacker and cannot make attacks of
opportunity. A character who is flat-footed because they were Surprised (a
failed surprise/Perception check at the start of combat) stays flat-footed
through the surprise round and until they take their first real action. This
is distinct from being Stunned: the flat-footed character can still act, they
simply have not yet reacted, and their reflexes are not yet in the fight.
Rules Reference
Field
Value
Duration / Default Formula
until the character takes their first action (surprise round / round one)
Duration / Type
variable
Prevented By
Uncanny Dodge (feat or augment), High initiative / successful surprise check
Prevents
Attacks of opportunity
Stacking
replace
Effects
description: Lose Dexterity bonus to AC against all attackers.
Field
Value
description
Lose Dexterity bonus to AC against all attackers.
modifier
no-bonus-to-ac
target
dexterity
description: Cannot make attacks of opportunity.
Field
Value
description
Cannot make attacks of opportunity.
modifier
disabled
target
opportunity-attacks
Remove Conditions
description: Take the first action in the round; the character has reacted.
Field
Value
description
Take the first action in the round; the character has reacted.
description: Round ends and the surprise window closes.