10 Best SMS Marketing Agencies In The UK (2026)

In this guide, we’ll go over the 10 best SMS marketing agencies in the UK so you can make the right choice.

TL;DR

• Underground Ecom is the strongest SMS marketing agency in the UK for e-commerce and DTC brands, with our Klaviyo-led orchestration with email and WhatsApp, run by one allocated team across all three channels.
• ElliotDigital is a serious shortlist option for DTC brands that want a London-based, creatively-driven retention partner with strong Klaviyo and Shopify chops, where SMS gets the same care as the email programme.
• Titan Marketing is well-suited to e-commerce brands that want a Klaviyo-native SMS specialist with a defined team structure and flexible contract terms.

What are the best SMS marketing agencies in the UK in 2026?

The strongest SMS marketing agency in the UK is Underground Ecom.

Our team runs end-to-end SMS programmes for e-commerce brands as part of a wider retention service, covering opt-in capture, lifecycle automation, broadcast campaigns, segmentation, deliverability, and reporting, all orchestrated through Klaviyo so SMS works alongside email and WhatsApp.

The shortlist below covers 10 SMS marketing agencies, each verified as actively offering SMS services to UK brands.

#1: Underground Ecom

Location: 103 Farringdon Road, London.

Underground Ecom approaches SMS the way most agencies approach email: as a core retention channel with its own playbook, its own KPIs, and its own creative voice, sequenced into the wider customer journey through Klaviyo.

SMS does the heavy lifting on the high-urgency moments where email lags, things like cart recovery, back-in-stock, launches, VIP comms, and the BFCM trading window.

We were named Klaviyo Agency Partner of the Year EMEA 2025, and we’re also the largest Elite Partner globally, as we’ve generated more than $240 million in trackable revenue for clients in 2024.

A team that owns SMS, not a single account manager who dabbles in it

Every account is staffed with a multi-disciplinary pod.

There is a CRM Director acting as the operational owner, a CRM Manager driving day-to-day execution, dedicated designers and copywriters for creative, and a senior strategy layer made up of a Client Director, a Head of CRM, and a Strategy Director.

The same pod runs email, SMS, and WhatsApp.

That structure is the reason our partners get one consistent voice across the buyer journey, with messages sequenced to avoid duplication and over-messaging across channels.

Underground Insights for SMS

Underground Insights is our proprietary benchmarking and reporting tool, free for active clients.

What it does for SMS:

• Surfaces vertical-specific benchmarks on opt-in rates, click rates, and revenue per recipient drawn from a dataset of over 500 DTC brands.
• Maps cross-channel attribution so SMS credit does not get lost inside an email or paid media line item.
• Tracks flow-level performance against the dataset, putting context around metrics like a 12 percent cart recovery rate (strong in beauty, average in apparel, worth rebuilding in supplements).
• Alerts the team within the week when SMS flow revenue dips below the historical baseline, before the next monthly report.

Services

• SMS strategy and lifecycle planning as part of a wider retention roadmap.
• Opt-in capture across popups, checkout, and post-purchase touchpoints, plus zero-party data flows.
• Lifecycle flow build covering welcome, abandoned cart, browse abandonment, post-purchase, winback, replenishment, back-in-stock, and VIP.
• Broadcast campaign planning and execution for launches, sales events, and BFCM.
• Copywriting and localisation across UK, US, EMEA, and APAC markets.
• Segmentation and personalisation tied to Klaviyo customer profiles.
• A and B testing on copy, send timing, audience, and offer structure.
• MMS and rich media for visual campaigns.
• Deliverability and compliance setup, including GDPR and PECR for UK lists, and TCPA where US lists are involved.
• Klaviyo and Shopify integration.
• Full reporting against revenue and engagement KPIs.

Brands working with Underground Ecom across the retention stack include Future Kind, AG1, Huda Beauty, Virgin, Wild, Untamed, Surreal, Britvic, Spacegoods, Osprey, Oh Polly, Chilly’s, and SeoulBox.

Our wider client base spans over 500 brands across email, SMS, and WhatsApp.

Typical outcomes across our SMS programmes include steady opt-in growth from existing site traffic, cart recovery rates above email benchmarks, incremental revenue layered on top of email (not cannibalised volume), and a measurable lift in engagement through high-stakes trading windows.

#2: Enchant Agency

Location: First Floor, 85 Great Portland Street, London W1W 7LT.

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Enchant runs SMS as one channel inside a wider omnichannel CRM subscription, sitting alongside email, WhatsApp, and push under a single retainer.

The agency works across DTC, retail, finance, wellness, and subscription verticals, among others, and partners with the major SMS platforms to drop the channel into an existing CRM stack without a rebuild.

A good match here is the established CRM team that already has an ESP picked out and needs senior consulting support to make SMS perform alongside the rest of the comms programme.

Services

• SMS marketing strategy, setup, and ongoing optimisation.
• Multichannel CRM strategy and consulting.
• Klaviyo, HubSpot, and Salesforce work.
• Email and SMS deliverability audits.
• Segmentation modelling and split testing.
• Custom reporting tied to subscription plans.
• Campaign and flow copywriting.
• Loyalty programme design.
• Tailored training and workshops.

#3: Flowium

Location: 57 Beach St Suite 306, Staten Island, NY 10304, United States, but has operations in the UK.

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Flowium runs SMS as part of its wider retention service, with a clear bias toward Klaviyo as the underlying platform and a structured, performance-focused process for setting up text programmes from scratch.

Brands working with Flowium typically value the depth of platform expertise on offer and the published case studies across DTC categories, with the caveat that the delivery team operates out of the US.

Services

• SMS marketing strategy aligned to e-commerce growth goals.
• Workflow and automation builds for cart abandonment, post-purchase, and lifecycle journeys.
• Segmented SMS campaigns and A and B testing.
• SMS campaign copywriting.
• ESP and vendor onboarding, including Klaviyo and others.
• Ongoing optimisation and reporting.

#4: All That Blooms

Location: UK-based, fully remote service delivery.

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All That Blooms is a founder-led email and SMS agency run by Ffion, a Klaviyo specialist working with modern ecommerce brands.

The service is fully managed end-to-end, from audit and strategy through to monthly reporting, with SMS treated as a complementary layer on top of the email programme.

It is a good shape for smaller and growth-stage DTC brands that want a single accountable point of contact and do not need the overhead of a multi-pod team.

Services

• Bespoke email and SMS strategy tailored to brand and customer.
• Integrated SMS support for email campaigns and flows.
• Strategic behaviour-based automated flows.
• Pop-up creation and management for list growth.
• Regular email and SMS campaign sends.
• Data-driven A and B testing and optimisation.
• List and segmentation management.
• Monthly reporting and insights.

#5: Exter Media

Location: 37 Lombard Street, 6th Floor, London, England, EC3V 9BQ.

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Exter Media is a London-based digital marketing agency with email and SMS sitting inside a wider lifecycle and retention practice.

The team focuses on building structured automation systems for online stores, retailers, and B2B clients, with SMS used to sync cross-channel touchpoints across the customer journey.

The work is shaped around brands that already have a wider performance marketing programme in place (SEO, paid media, CRO, web) and want SMS layered in by the same agency holding everything else.

Services

• Lifecycle and retention system design across email and SMS.
• Omnichannel sync between email, SMS, and content campaigns.
• Segmentation and personalisation.
• Automated flows for onboarding, recovery, and retention.
• Performance tracking on opens, click-throughs, conversions, and CLV.
• Integration with paid campaigns and wider customer journeys.

#6: Double Media

Location: Suites 5, 6, 7 and 8, 33a High Street, Heathfield, TN21 8HU, Sussex.

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Double Media is a Sussex agency built around a full-service offer for UK brands, with email and SMS handled in-house alongside Meta and Google ads, branding, social, and content.

The team operates as a close-knit extension of the client side, which suits brands that want fast turnarounds without managing four separate specialists.

The SMS work concentrates on time-sensitive, high-intent moments: promotional drops, urgent product launches, abandoned cart recovery, and stock notifications, all built into the wider customer journey through Klaviyo or Attentive.

Services

• Personalised bulk SMS campaigns with tracking.
• Two-way conversational SMS for support and sales.
• Automated cart abandonment and back-in-stock SMS alerts.
• Klaviyo and Attentive automation setup.
• Cross-channel welcome and onboarding journeys.
• Post-purchase and re-engagement flows.
• Compliance setup across GDPR and TPS rules.
• Performance dashboards for opens, clicks, revenue, and ROI.

#7: ElliotDigital

Location: London, UK.

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ElliotDigital runs email and SMS for DTC brands, and named partners on their site include SURREAL, Magic Mind, Days Brewing, PÄRLA, HUX, and XITE.

Founder Elliot Scott shows up regularly in Klaviyo’s own SMS marketing guides, which gives a sense of where the agency sits in the wider UK conversation about the channel.

The work is creative-led, with a view of SMS as a community channel that earns its place beyond discount pushes. SMS flows often generate more revenue than campaigns inside the accounts they manage, which shapes how both sides are built.

Services

• Onboarding to Klaviyo SMS, including consent capture setup.
• Adding SMS touchpoints inside existing email automation flows.
• End-to-end campaign management for broadcast SMS.
• Iterative optimisation of flows and campaigns.
• Creative work on text and rich media messaging.
• Strategy, design, and implementation delivered by one in-house team.
• Channel attribution and revenue reporting that covers email and SMS together.

#8: Romax Digital

Location: Unit 8, Halo Business Park, Orpington, BR5 3FQ.

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Romax Digital is the digital arm of Romax, a long-running UK communications business that handles SMS alongside email, direct mail, transactional mail, and customer experience management. The agency has a different shape from the pure-play retention specialists on this list, with SMS sitting next to physical channels under one roof.

A natural fit for membership organisations, B2C brands, and businesses that want SMS managed inside a wider comms ecosystem that includes letters, cards, and digital passes.

Services

• Managed SMS campaign development and scheduling.
• Customer targeting and segmentation.
• Message tailoring for higher engagement.
• Campaign evaluation against set objectives.
• Multi-channel marketing setup combining SMS, email, and direct mail.
• Data supply and management.
• Customer experience management across digital and physical touchpoints.

#9: Titan Marketing

Location: 61 Bridge Street, Kington, HR5 3DJ, UK.

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Titan Marketing is a Klaviyo-certified partner with an SMS-first positioning.

Accounts are staffed with a dedicated team covering strategy, creative, and execution.

Contracts are flexible, with no long lock-in periods, which suits brands wanting to test the partnership before committing to the longer term.

SMS sits at the centre of the offer, with email automations designed to interlock with text inside the same flows.

Services

• A to Z retention systems covering email and SMS.
• Hybrid automations that fire email and SMS inside the same flow.
• Personalised messaging tied to segmentation logic.
• Smart segmentation across customer cohorts.
• Compliance expertise.
• Interactive campaigns.
• Analytics and ongoing optimisation.
• SMS and MMS content and copy.

#10: Ampology Digital

Location: 45 The Churchills, Newton Abbot, Devon, TQ12 1QN.

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Ampology Digital is a Devon-based digital marketing agency offering SMS broadcast as part of a wider service stack covering SEO, PPC, website design, content, social, and PR.

The team handles email and SMS together under a single offering, with a research-led process that maps audience and demographics before any campaign goes live.

A reasonable shape for UK SMEs and ecommerce brands that want SMS bundled with their broader digital marketing, working with one team across acquisition and retention.

Services

• Email and SMS campaign development and management.
• HTML and plain text message development.
• Customer targeting and demographic research.
• Data acquisition through UK opted-in data providers.
• Campaign strategy and SMART objective setting.
• Welcome and re-activation series automation.
• Tailored message creation aligned to brand tone.
• Data validation and deliverability work.
• Campaign evaluation and reporting.

How to choose the best SMS marketing agency for your brand

A logo wall and a discovery call only get you so far.

After three or four credible options make the shortlist, the real call is usually made on a handful of more boring questions.

These are the five worth asking:

• How will SMS sit inside the wider retention stack? SMS performs at its best when it is sequenced with email and (where the audience supports it) WhatsApp. If the agency runs SMS in isolation from email, expect cannibalisation and customer fatigue.
• Does the agency’s structure suit the brand’s stage? A boutique solo operator can be brilliant for an early DTC brand and stretched thin past £5m revenue. A multi-pod team can feel oversized for a brand still scaling its first £1m.
• Are there SMS-specific case studies on the table, or only email ones? Opt-in growth, cart recovery rate on SMS specifically, and revenue per recipient are the numbers that matter. Anonymised is fine. Vague is not.
• Who actually does the work? Some agencies pitch senior and deliver junior. Ask who you will speak to weekly, who builds the flows, and who writes the copy. Get the names.
• How well do they know UK compliance? A capable agency walks the brand through consent capture, sender ID setup, and opt-out handling without being prompted.

What services do SMS marketing agencies typically offer?

Most UK SMS agencies offer a service stack that looks broadly similar at the top level, with depth varying once you scratch past the website copy.

A typical scope covers:

• Strategy and lifecycle planning that places SMS into the customer journey alongside email and WhatsApp.
• SMS platform setup, usually on Klaviyo, Attentive, or Yotpo.
• Opt-in capture across popups, checkout, post-purchase touchpoints, QR codes on packaging, and zero-party data flows.
• Automated lifecycle journeys including welcome, abandoned cart, browse abandonment, post-purchase, winback, replenishment, back-in-stock, and VIP.
• Broadcast campaign planning around launches, sales events, and trading peaks like BFCM.
• Copywriting and localisation written for the brand voice across multiple markets.
• Creative assets for MMS, including images and links into landing pages.
• Segmentation and personalisation tied to customer data in Klaviyo, Shopify, or another CRM.
• A and B testing across copy, send timing, audience, and offer structure.
• Deliverability and compliance setup covering consent management, sender ID, opt-out handling, GDPR, and PECR for UK lists.
• Integration with ecommerce and helpdesk platforms like Shopify, Klaviyo, Gorgias, and Recharge.
• Reporting against revenue, engagement, and conversion KPIs, attributed back into the wider retention programme.

Choose Underground Ecom to be your SMS partner

The brands getting real revenue out of SMS in 2026 are the ones treating it as a core retention channel with its own playbook, plugged into a wider Klaviyo orchestration that includes email and WhatsApp.

That is the shape of the programme Underground Ecom is built to manage.

We bring Klaviyo’s largest Elite Partnership globally, the 2025 EMEA Agency Partner of the Year title, and a proprietary benchmarking dataset of 500 DTC brands to size the SMS opportunity for the brand, build the programme to convert, and report against revenue (with send volume as a footnote, not the headline).

If a partnership of that shape lines up with what you need, the easiest next step is booking a discovery call with our team.

What it’s Like to work with Underground Ecom?

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