Getting online after a move runs into two separate walls: which network is physically available at the address, and whether a provider will accept a customer who has no BSN or Dutch bank account yet. Lead times also vary enormously by technology, which matters for anyone expected to work from home from day one.
KPN, Ziggo, and Odido are the three real options, and they run on different infrastructure. KPN owns most of the fiber network and is still actively expanding it, alongside legacy copper/VDSL in areas not yet upgraded. Ziggo runs on coax cable (part of VodafoneZiggo), which covers most cities regardless of fiber rollout. Odido — the rebrand of what was T-Mobile/Tele2 — resells KPN's fiber network and also offers a 5G home-internet product (Klik&Klaar) that needs no technician visit at all, just a router you plug in, which is genuinely useful as a stopgap. On the no-BSN problem: most providers want a BSN and Dutch bank account for the direct debit, and without one you'll often hit a wall or need to wait; policies shift, so it's worth calling rather than assuming. On timing: Ziggo can go live within days if the coax is already wired in; KPN fiber typically needs a technician appointment, commonly 1–3 weeks out depending on local backlog; Odido's 5G router can bridge the gap almost immediately while you wait for a fixed line. None is objectively "best" — it's about what's actually available at your address.