FOC Date: The Day Your Number Actually Moves

A FOC date (Firm Order Commitment date) is the specific date on which your current carrier has committed to release your phone numbers to your new carrier. The losing carrier issues the FOC after the port request validates against their records, and it is the anchor every other porting event hangs on — cutover, trunk testing, and the moment your old service stops mattering.

Operators treat the FOC date as “the day the port happens,” and for planning purposes that is close enough. But the FOC is a commitment, not the cutover itself — and understanding the difference explains why ports occasionally stall after the promised date, why a single corrected digit on the order can push your date back a week, and what you should actually have ready before the date arrives. The end-to-end process lives in our number porting guide; what follows stays on the FOC itself — who issues it, why it slips, and how to plan a cutover around it.

The FOC is the losing carrier’s promise, not the gaining carrier’s

Direction matters here. Your new carrier submits the port order — formally, a Local Service Request (LSR) — to your current carrier. The current (losing) carrier checks that order against its own customer records: account number, authorized name, service address, PIN if one exists. Only when everything matches does the losing carrier respond with a Firm Order Commitment: these numbers, released on this date, often within a stated activation window.

So the FOC is issued by the carrier you are leaving, to the carrier you are joining. Your new carrier cannot manufacture a FOC date, move one unilaterally, or promise one before the losing carrier has validated the order. When a sales rep quotes you a port completion date before the LSR has even been accepted, they are guessing. A real date exists only once the FOC comes back.

That validation step is also why the FOC arrives days into the process rather than immediately. If any field on the order fails to match the losing carrier’s records, you get a rejection with a reason code instead of a FOC, and the correction-and-resubmit cycle starts. (If you have read that the FCC requires ports to finish in one business day, that rule measures a different clock — the losing carrier’s turnaround on a qualifying single-line request — and the timeline section of our porting guide explains why the realistic end-to-end window is still 7 to 14 business days.)

FOC date versus activation: the commitment is not the cutover

Here is the distinction that trips people up: the FOC date is when the losing carrier agrees to let go. The actual routing change is a separate event — on or around the FOC date, the gaining carrier activates the numbers in the NPAC, the national portability database, which then broadcasts the new routing to every carrier’s local copy. Calls start flowing to the new network at that moment of activation, not at midnight on the FOC date. (What the routing key itself is, and why billing follows it, is covered in what an LRN is.)

Two practical consequences:

A FOC date can pass without the port completing. If the gaining carrier does not trigger activation, the numbers do not move — and if activation never happens, the numbers can eventually revert to the losing carrier. This is rare with a competent carrier, but it is why “the FOC date was yesterday and my calls still route to the old system” is a real support ticket, and why the correct escalation is to the gaining carrier’s porting desk, not the carrier you left.

Cutover timing within the day is approximate. FOCs often specify a window rather than an instant. Plan for the port to complete at some point during business hours on the FOC date, not at a precise minute.

Why FOC dates slip

A FOC is firm the way a contractor’s start date is firm: it holds until something touches the order. The common triggers:

• Supplements reset the clock. Any change to the port order after the FOC is issued — a corrected account number, an added or removed number, a customer-requested new date — is a supplement, and a supplement can reissue the FOC with a later date. One wrong digit discovered late costs you the original date.
• Late rejections. Occasionally a losing carrier issues a FOC and then finds a problem (a pending order on the account, a partial-port complication with the billing telephone number). The FOC is withdrawn or rescheduled while the issue clears.
• Customer reschedules. You can usually move a FOC date, but not casually and not last-minute — most losing carriers require cancellation or reschedule requests several business days before the committed date. Inside that window, expect the original date to execute.
• Volume and complexity. Large blocks, multiple losing carriers, or numbers spread across systems mean multiple FOCs that rarely land on the same day. Treat a multi-carrier port as several ports with several dates.

The single best defense is boring: get the account information exactly right on the LOA and the LSR before submission, so the first FOC you receive is the only one you need.

Build your cutover plan backward from the FOC date

Once the FOC is in hand, everything else has a deadline:

• Before the FOC date: have your new trunk configured and tested with fresh numbers, so ported numbers land on a system that already works. Our SIP trunk configuration guide covers that setup. Confirm inbound routing (ring groups, IVRs, queues) is mapped for the incoming numbers.
• On the FOC date: keep the old service untouched — do not cancel anything with the losing carrier ahead of the port, because the port itself terminates service for the ported numbers. Test inbound and outbound on each number once activation lands.
• After the FOC date: verify caller ID and CNAM behavior, confirm your numbers are signed correctly for STIR/SHAKEN attestation, and audit the losing carrier’s final invoice so billing actually stopped. The post-port checklist in the porting guide walks through each item.

Scheduling advice from the trenches: put the FOC date early in the week if you can choose it. If anything needs escalation, you want porting desks staffed the next morning, not a weekend between you and a fix.

Frequently asked questions

The FOC date is only as useful as the plan built around it, and coordinating that cutover is the part SIPNEX handles: as an FCC-licensed carrier we manage the LSR and FOC exchange so your ported numbers land on a SIP trunk you have already configured and tested, signing at A-level attestation under our own STIR/SHAKEN certificate from the first post-port call. Start your port or review wholesale rates.