Fifteen days. That’s how long the FCC gives a caller, after a landline number moves to a wireless carrier, before a prerecorded or autodialed voice call to it can create liability under the cell-phone rule. The safe harbor is narrow: voice calls only, no knowing calls, and nothing on a Do Not Call list. A company that scrubs its call lists against port data every day, and keeps the scrub records, can usually show that a call to a freshly ported number falls inside it.
Why does porting a landline create TCPA exposure?
Because the stricter rule follows the number’s current service, not the service it had when the list was built. The FCC’s rule at 47 C.F.R. § 64.1200(a)(1)(iii) bars autodialed and artificial or prerecorded voice calls, absent an emergency or consent, to numbers assigned to a “cellular telephone service” and to other wireless and paid services listed in the rule.
A landline gets different treatment. The residential-line rule in § 64.1200(a)(3) reaches prerecorded calls that carry an advertisement or constitute telemarketing, and it carries its own exemptions, which the earlier post on prerecorded calls to landlines walks through. So a prerecorded informational call that’s fine on Monday to a home phone can become a claim on Tuesday, after the subscriber moves the number to a cell carrier. Nobody told the caller, and the number itself looks the same.
What does the ported-number safe harbor say?
It excuses a short window of calls under the cell-phone rule. Section 64.1200(a)(1)(iv) provides that a person “will not be liable for violating the prohibition in paragraph (a)(1)(iii) of this section when the call is placed to a wireless number that has been ported from wireline service and such call is a voice call; not knowingly made to a wireless number; and made within 15 days of the porting of the number from wireline to wireless service, provided the number is not already on the national do-not-call registry or caller’s company-specific do-not-call list.”
Break that into its parts and there are five conditions. The number moved from wireline to wireless service. The call was a voice call. The caller didn’t know it was calling a wireless number. The call came within 15 days of the port. And the number wasn’t on the national Registry or the caller’s internal do-not-call list. Miss any one and the safe harbor is gone.
Where did the 15 days come from?
A 2004 FCC order. When wireline-to-wireless number portability began in November 2003, callers had no way to learn of a port the moment it happened. In FCC 04-204, adopted August 25, 2004, the Commission explained that “this limited safe harbor period is necessary to allow callers to comply with this statutory provision.” The order tied the start of the window to two events: completion of the port, and the number’s appearance as wireless in the industry’s port-identification data.
Business commenters asked for 30 days or more. The FCC said no. The order states “We decline to adopt a safe harbor period that extends beyond 15 days as suggested by several commenters.” It found 15 days enough time for port data to reach callers and get scrubbed from their lists.
Which calls does the safe harbor not cover?
Text messages, to start. The FCC was explicit: the safe harbor “will extend only to voice calls, not to text messages, which are sent specifically to numbers associated with wireless devices.” A company that texts a number that just moved to a cell carrier gets no 15-day cover, though most texting platforms don’t send to landlines in the first place.
Knowing calls are out too. The order says that “even within the 15-day safe harbor period, persons will be considered in violation of this prohibition if they knowingly place an autodialed or prerecorded message call to a wireless number absent an emergency or the prior express consent of the called party.” If the subscriber told your agent last week that the number is now a cell phone, the window doesn’t help.
Do Not Call claims fall outside it. The safe harbor answers only a claim under § 64.1200(a)(1)(iii), and it doesn’t apply at all to a number already on the Registry or the caller’s internal list. The FCC said in FCC 04-204 that it “in no way obviates the need for telemarketers to abide by any of the Commission’s other telemarketing rules including honoring the requirements of the national and company-specific do-not-call lists.”
And the FCC refused to stretch the idea into a general good-faith defense. The same order states “We also decline to extend our safe harbor provision to any call made erroneously or inadvertently to a wireless number regardless of whether that number has been recently ported from wireline service.” A caller who dials a cell phone it thought was a landline, with no recent port, has to defend on consent or on the equipment.
| Situation | Safe harbor? | What actually answers the claim |
|---|---|---|
| Prerecorded voice call within 15 days of a wireline-to-wireless port | Yes, if the caller didn’t know and the number wasn’t on a do-not-call list | Port-data scrub records and the call date |
| Same call on day 16 or later | No | Consent, or an emergency purpose |
| Text message to a newly ported number | No | Consent, or the equipment argument |
| Number already on the national Registry | No | Do Not Call defenses, such as written procedures or an established business relationship |
| Wireless number misidentified as a landline, no port | No | Consent, or the equipment argument |
Does the safe harbor still matter after Duguid?
More for prerecorded calls than for autodialed ones. Since the Supreme Court narrowed the autodialer definition in 2021, most dialing systems that call from customer lists don’t qualify, and the earlier post on autodialer defenses after Duguid covers that argument. A prerecorded or artificial voice is different. It triggers § 64.1200(a)(1)(iii) no matter how the number was dialed, and the FCC’s 2024 declaratory ruling, FCC 24-17, treats AI-generated voices as artificial voice. So the companies that need this safe harbor most are the ones sending recorded reminders, collection messages, and voice broadcasts to lists that still carry old landline numbers.
There’s also the post-2025 question every FCC rule now faces. After McLaughlin Chiropractic Associates v. McKesson Corp. (2025), district courts in private suits read the TCPA for themselves. The ported-number safe harbor is a codified regulation adopted through rulemaking, which puts it on firmer footing than an informal FCC interpretation. A defendant relying on it should still be ready to explain why a 15-day grace period fits the statute, and the FCC’s own reasoning, that a rule without one would require callers to know what they can’t, is the place to start.
The safe harbor is easy to lose through bad recordkeeping. A company that scrubs against port data but can’t produce the file showing when it ran, and what it flagged, is left arguing about dates from memory. TCPA defense counsel will ask for that file first, because the 15-day window is proved or lost on it.
What to pull when a ported-number claim arrives
- Put a litigation hold on the dialer or voice-broadcast logs for the number, the consent record if one exists, and the recorded or AI-voice message files the campaign used.
- Export the internal do-not-call list and any opt-out or wrong-number notes for the number, with dates, to rule out a knowing call.
- Pull the port-data and wireless-identification scrub records for the campaign, the date of each scrub, and the Registry download used, which has to be from no more than 31 days before the call under § 64.1200(c)(2)(i)(D).
- Gather the contracts with the dialing platform, list vendor, and scrub provider, along with the call scripts.
- Have a lawyer review the file before answering the demand, calling the plaintiff, or proposing a payment.
Questions about ported numbers and the TCPA
Does the safe harbor apply when a cell number is ported to a landline?
No. The rule covers a “wireless number that has been ported from wireline service,” and a call to a landline isn’t a cell-phone claim anyway. A number moved from wireless to wireline may raise questions under the residential-line rule instead, and those turn on the content of the message and the exemptions for that rule.
Who has to prove the call fell inside the 15 days?
In practice, the caller. The safe harbor is a defense to an otherwise covered call, and the facts that establish it, the port date and the absence of knowledge, sit in the caller’s own records and its vendors’ data. A company that can’t show when it learned of the port will have a hard time using the window.
What damages apply if the safe harbor doesn’t?
A private plaintiff can recover up to $500 per call under the robocall provision of 47 U.S.C. § 227(b)(3), and a court may increase that to up to three times the amount if it finds the violation was willful or knowing. Wrong-number and ported-number cases sometimes come as class actions, where the per-call figure multiplies.
Is checking a number once enough?
No. Ports happen every day, and the window runs from the port, not from the caller’s last scrub. A list checked once at upload can carry a ported number for months. Daily scrubbing against current port data is the only way the 15 days does any work.
Defending calls to recently ported numbers
If your company has been sued over prerecorded or autodialed calls to a number that used to be a landline, the port date and the scrub records usually decide whether the safe harbor applies. Rosenberger + Kawabata represents businesses defending TCPA lawsuits and class actions through its business litigation practice, including claims involving prerecorded calls to ported numbers. Contact Rosenberger + Kawabata online for a confidential consultation, or call (310) 894-6921.
Sources
The statute is the Telephone Consumer Protection Act, 47 U.S.C. § 227. The FCC’s rules are at 47 C.F.R. § 64.1200, as published in the eCFR on July 1, 2026. The order that adopted the ported-number safe harbor is the FCC’s Order in CG Docket No. 02-278, FCC 04-204 (released Sept. 21, 2004).
This post is general information about the Telephone Consumer Protection Act and related laws as of July 6, 2026. It is not legal advice, and reading it does not create an attorney-client relationship. Courts and the FCC change the rules in this area often, and the outcome of any claim depends on its facts. Past results do not guarantee future outcomes.