How long must I have worked for the company before a Dutch ICT transfer?

The ICT route requires an existing employment relationship within the group. You need to have worked for the company outside the EU, EEA or Switzerland for at least three months immediately before the transfer to the Dutch branch.

This prior-employment condition is central to the permit, so keep clear evidence of your length of service and your role with the foreign employer, as the IND will check that the transfer is genuine and within the same company group.