A number porting playbook for multi-country estates
Porting a few hundred numbers across five countries is five different projects wearing one name. This is how we run them - the letters of authorisation, the realistic timelines per market, and the pitfalls that turn a two-week port into a two-month one.
Porting is a legal process before it is a technical one - In every country we operate in, moving a number from one carrier to another is governed by the regulator, executed between the losing and gaining operators, and triggered by a document in which the number's legal owner authorises the move. The technical part, repointing the number to a new SIP endpoint, takes seconds. Everything that can go wrong happens in the paperwork. Treat a multi-country port as a set of parallel regulatory workflows with a shared cut-over plan, and it becomes predictable.
The letter of authorisation is where most rejections are born - Every market has some form of LOA (a Letter of Authorisation, sometimes called a porting request or a transfer form), and every losing carrier will reject it if the details do not match their billing record exactly. The name on the LOA must be the legal entity that holds the account, not the parent company or the brand. The address must be the service address on the account, not head office. The signatory must be someone the losing carrier will accept as authorised, and in several markets the account number, customer reference or a port-out PIN must appear. Before you sign anything, get the current provider's customer record and copy the details from it. In the United States that record is called a CSR; in the UK it is usually the latest bill; in France you will need the RIO code that identifies the line; in India a Unique Porting Code is generated by SMS from the number itself.
Timelines differ by an order of magnitude - A simple single-line port in the United States or Canada can complete in one to three business days once the LOA is accepted, but multi-line ports take longer, and toll-free numbers move through a RespOrg change rather than a standard port. In the UK a geographic number port typically completes within one to two weeks, longer for large DDI ranges. Germany, the Netherlands and France usually land in the same range, subject to the losing carrier's contract terms. Australia distinguishes simple and complex ports, and a complex port involving ISDN or large ranges is measured in weeks. In India, mobile numbers port in a few working days via the UPC process; fixed numbers can rarely be ported outside their service area, and the practical answer is often new local numbers plus forwarding during a transition. Plan the project around the slowest country, not the fastest.
Not every number can move to the trunk you want - Numbers carry a regulatory category, and they cannot cross it during a port. A geographic number stays geographic; a mobile number cannot become a fixed number; a toll-free number moves only to a carrier that offers toll-free in that country. Many countries also require the gaining customer to have a registered entity or a service address in the number area, so a Singapore number cannot be ported to a customer with no Singapore KYC file. Check that the destination product exists before you promise a date, and check that the numbers actually belong to the entity signing the LOA. Resold and white-labelled numbers are the classic trap: the enterprise thinks it owns them, the reseller's carrier thinks the reseller does.
Contract terms and outstanding balances stop ports quietly - Losing carriers can, and do, reject a port when the account is in arrears or the numbers are inside a minimum term, and some will not tell you why. Before submitting, settle the account, confirm the notice period, and understand whether cancelling the old contract will disconnect the numbers before the port completes. Never cancel the old service yourself. A number the losing carrier has disconnected is no longer portable and may already be back in the operator's pool.
Batch the estate, and port the boring numbers first - We split every large project into batches by country, by losing carrier and by criticality. The first batch is deliberately unimportant: a small range of low-traffic numbers that validates the paperwork, the cut-over process, the inbound routing and the customer's own dial plan. Contact-centre and published customer-service numbers go last, once everybody has seen a batch complete cleanly. Small batches also contain the fallout of a partial acceptance, where the losing carrier ports some numbers on the day and rejects others.
Cut-over day is about what stays working, not what moves - On the porting date the losing carrier releases the range at a time it chooses within the agreed window, so inbound calls can arrive on the new trunk at any point that day. Have the new routing configured and tested with a temporary number the week before. Keep the old service alive until the port confirms. Update emergency-services address records for the ported numbers the same day; in the UK, the US and Australia this is a compliance requirement rather than a nicety. Then check every attached service - fax lines, alarm panels, payment terminals, IVR entry points and any third-party platform that had the number hard-coded.
What to hand your carrier at the start - The fastest ports we run start with a spreadsheet: every number, its country, its current carrier, its category, the legal entity and address on the account, the account reference, and the number's role in the business. Attach the current bills, and tell us which numbers cannot be down for a minute and which ones nobody would notice. With that, our porting desk can tell you within a day which numbers will port, which will need new numbers and forwarding instead, and roughly how long each country will take. Without it, the first two weeks of any multi-country port are spent finding out.
