A legally married spouse and unmarried children under twenty-one qualify for L-2. The L-2 spouse is employment-authorized incident to status; L-2 children may study but may not work.
A working spouse is a reason to prefer this route
For a household where both adults earn, the L-2 spouse rule often outweighs other considerations, because the spouse may take employment without waiting for a separate authorization document and without being tied to the principal's employer. Children may enrol in school and lose derivative eligibility at twenty-one. Two planning points follow from Fabien's eighteen-month assignment.
First, a short posting still requires the family to arrange schooling, health cover and tax filings, and the immigration status answers none of those. Second, if the assignment is extended, the five-year L-1B maximum caps how long the family can rely on this arrangement, so any longer plan needs a different route identified in advance. A common-law partner does not qualify as a spouse for these purposes and would need an independent basis to accompany him.