Skills

Open Lock (Dex; Trained Only)

Attempting an Open Lock check without a set of thieves' tools imposes a -2 circumstance penalty on the check, even if a simple tool is employed. If you use masterwork thieves' tools, you gain a +2 circumstance bonus on the check.

The DC for opening a lock varies from 20 to 40, depending on the quality of the lock, as given on the table below.

Lock
DC
Lock
DC
Very simple lock
20
Good lock
30
Average lock
25
Amazing lock
40

Action: Opening a lock is a full-round action.

Special: If you have the Nimble Fingers feat, you get a +2 bonus on Open Lock checks.

Untrained: You cannot pick locks untrained, but you might successfully force them open.

Epic Use

The character can open locks more quickly than normal.

Open lock as . . .
DC Modifier
Move-equivalent action
+20
Free action
+50

Source: SRD 3.5 Combined Skills