Klaviyo SMS During BFCM: Quiet Hours and Compliance

An SMS lands on the lock screen. During a promotional weekend, its timing and consent rules therefore weigh more than those of email. This article goes through what Klaviyo's documentation says about quiet hours in campaigns and flows, Smart Sending, consent and deliverability, with the 2026 BFCM calendar in mind. For SMS activation in France and the CNIL framework, two articles already exist: the Klaviyo SMS guide for France and the one on GDPR and the CNIL for SMS.

TL;DR. In France, Klaviyo's documentation states that carriers enforce quiet hours: no sending before 8 a.m. or after 10 p.m., nor on Sundays or public holidays. Klaviyo does not deliver messages to French recipients during those hours, campaigns included, with flow exceptions detailed below. In a campaign, you choose between delaying and skipping the message. In a flow, the message waits in a queue and the journey is paused. In our view, Sunday, November 29, 2026 should be treated as an SMS-free day in the plan.

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The BFCM calendar against French quiet hours

Klaviyo's page on quiet hours in flows gives, for France, a no-send range: before 8 a.m., after 10 p.m., every Sunday and public holidays (Klaviyo, understanding text message quiet hours in flows). It specifies that these rules are enforced by carriers: sending on a Sunday may be legally allowed, but the messages are not delivered, and carriers may filter other messages if you keep sending outside the hours.

On the 2026 calendar, that gives:

According to the page, transactional messages, the first message of a welcome flow and Shopify post-purchase flows are exceptions in Klaviyo (details below). In our view, a Sunday reminder, common in email, does not work for SMS: it moves to Saturday during the day or to Monday from 8 a.m. Our BFCM send calendar describes the matching email sequence.

In campaigns: delay or skip

Klaviyo has a dedicated page on quiet hours in SMS campaigns (Klaviyo, quiet hours in campaigns). The check is made recipient by recipient, at send time, based on the location and time zone stored on the profile. Two people can therefore receive the same campaign at different times.

At the scheduling step, you choose what happens to a message that would fall inside a recipient's quiet hours:

Delay is the default. You can set a maximum delay on it: if the next allowed slot falls beyond that threshold, the message is skipped instead of waiting indefinitely.

A few reading notes:

• A campaign shows the Sent status as soon as messages start going out, even if some are still delayed. The breakdown of sends and delays is on the Campaign Overview page.
• Delayed recipients have a Quiet Hours Delay Duration field on the Received Text Message event in their activity log.
• Skipped recipients are classified Skipped: Quiet Hours in recipient activity, Skipped tab.
• The page recommends letting delayed messages finish before evaluating campaign performance.

In our view, a flash sale that ends at midnight is scheduled as Skip. A teaser SMS the day before launch can accept Delay with a short maximum delay. In both cases, the decision is made before scheduling.

In flows: the waiting queue pauses the journey

In a flow, an SMS due during quiet hours waits in a Waiting queue. In the meantime, the recipient does not move on in the flow: they pass neither the splits, nor the delays, nor the emails that follow. Once quiet hours end, the SMS goes out and the person resumes the journey. Flow filters are checked after the SMS is sent. Send Now and adding past profiles do not bypass quiet hours.

Three points from the page:

• Messages marked transactional have no quiet hours by default, but you can turn them on.
• In France, quiet hours do not apply to transactional messages or to the first message of a welcome flow, provided the flow uses the Subscribed to Text Messaging Marketing metric as its trigger. Another line of the page also mentions Shopify post-purchase flows.
• Quiet hours are checked before Smart Sending: a delayed message, once quiet hours have passed, is then subject to the Smart Sending window and may be skipped if it is still open.

The number of people waiting appears in the message's analytics, on the Waiting line. Our article on last-minute flows points out that this behavior can also delay the emails in the same journey.

SMS Smart Sending: a counter separate from email's

According to the SMS settings page, the default Smart Sending window is 24 hours, adjustable, and it is separate from the email window (Klaviyo, understanding your text message settings). After an email, you can therefore still send an SMS the same day. Klaviyo advises enabling Smart Sending, especially if you also send emails. Our article on Smart Sending and BFCM frequency details how it works on the email side.

In our view, for a four-day weekend, the useful question is the number of SMS per subscriber over the period, on top of the 24-hour window. A plan of two or three SMS at most, decided in advance, is easier to control than a frequency rule patched in along the way.

Consent and content: the basics

The "Basics: SMS compliance" page lists seven points (Klaviyo, basics: SMS compliance). It states that it is informational and does not replace legal advice. For a BFCM plan, four points need checking:

1. Consent. Only people currently subscribed can receive an SMS, in flows and campaigns alike. SMS consent is separate from email consent: the same checkbox, or general marketing consent, is not enough. A sign-up collected through third parties or from a purchased list is not valid.
2. The disclosure. It must appear wherever consent is collected: popup, embedded form, checkout page, printouts with a QR code, emails with a sign-up link.
3. Brand identification. The company prefix is optional except in France, where it is required, according to the SMS settings page.
4. Prohibited content. Some topics are filtered or blocked by carriers (the page cites alcohol, tobacco and gambling, among others), including on the website or linked page. In our view, these filters matter on a weekend when you add links to promotion pages.

On sender identity, the branded sender ID is the default in France according to the sending numbers page, but it cannot receive messages (Klaviyo, understanding SMS sending numbers). That rules out sign-up or opt-out keywords, two-way conversations and double opt-in by SMS. Our Klaviyo SMS guide for France details this constraint and unsubscribing by link.

A message skipped for lack of consent appears in the flow's Skipped tab with the reason Missing SMS Consent (Klaviyo, troubleshooting why a flow message skipped a profile).

Deliverability at peak: reading statuses with care

Klaviyo's SMS deliverability page notes that, for a small percentage of messages, carrier delivery receipts can arrive very late, or never, more often at peak hours such as Black Friday and Cyber Monday (Klaviyo, understanding and reviewing your SMS deliverability). The delivery status of a Received SMS message is then Delivered if the carrier confirmed, or Sent if it confirmed or refused nothing. A Sent SMS is therefore not necessarily lost.

The failure reasons to watch: device disconnected, device unreachable, carrier violation, message blocked, device incapable of receiving SMS, unknown. For Carrier Violation or Message Blocked, the page invites you to review the message, the link and the landing page.

One best practice cited by the page is to send at least 2 to 6 SMS per month, and at least one per month even to unengaged subscribers. In our view, that rules out the "first SMS of the year on Black Friday" strategy: a list woken up all at once risks unsubscribes and filtering you discover too late. A preparation send in October or early November, outside the promotion period, puts the list back in rhythm.

SMS checklist before BFCM

These points are Deliver's advice.

1. The SMS plan excludes November 11, Sunday November 29, and any slot before 8 a.m. or after 10 p.m.
2. Each campaign has an explicit Delay or Skip choice, with a maximum delay for Delay.
3. The maximum number of SMS per subscriber over the weekend is set, and SMS Smart Sending is checked.
4. SMS flows are reviewed with the Waiting queue in mind: a waiting SMS also holds up the rest of the journey.
5. Collection forms carry the disclosure, and SMS consent is separate from email consent.
6. The brand prefix appears in every SMS.
7. Links and landing pages are reviewed for content that carriers filter.
8. One person is designated to read the Delivered and Sent statuses without jumping to conclusions, and to watch the failure reasons.

FAQ

Can you send a marketing SMS on a Sunday in France with Klaviyo?

The page states that carriers enforce quiet hours on Sundays and public holidays, and that Klaviyo does not deliver messages to French recipients during those periods, campaigns included. Flow exceptions exist: transactional messages, the first message of the welcome flow, Shopify post-purchase flows.

What is the difference between Delay and Skip in an SMS campaign?

Delay holds the message until the recipient's quiet hours end, with an optional maximum delay. Skip does not send it at all. The page advises Skip for time-sensitive messages such as a flash sale.

Does an SMS waiting because of quiet hours block the rest of the flow?

Yes. The recipient stays in the Waiting queue and the journey is paused until the SMS is sent.

Are SMS Smart Sending and email Smart Sending linked?

No. They are counted separately: after an email, an SMS can go out the same day. The SMS window is 24 hours by default.

Why do my SMS stay at the Sent status?

Because the carrier has not confirmed delivery. These receipts can be very late at peak hours such as Black Friday.

Want an outside look at your SMS plan? We run Q4 readiness audits, or you can talk directly with the Deliver team.