The spouse needs their own appropriate work permission; the principal’s assignment does not extend to the household.
Review the actual proposed activity
Qualifying L spouses may work incident to appropriate status with required evidence. A customer badge or pending family case is not employment authorization.
Because dependent permissions derive from the principal's, the whole family reaches the same terminal date together, which is worth naming out loud rather than discovering when an extension is refused. The principal’s L-1B classification still rests on the qualifying relationship, continuous full-time foreign year within the prescribed three-year period, and specialized-knowledge duties. Since L-1B is capped at five years, the derivative timeline is bounded by whatever time the principal has left — which matters most when a child is approaching that birthday or a spouse is negotiating a multi-year role. If the principal's position is affected, the dependants' position may follow it, and the order of work matters: the principal's question is resolved first and household plans are made against the answer rather than in parallel with it. A technician on a short installation assignment may choose to travel alone and have the family visit as visitors; that is a legitimate plan, but visitors may not work or enrol in a full course of study.