6 Best SEO Agencies in London (2026)
London is the largest SEO market in Europe, with a mix of full-service performance agencies and narrow technical specialists. We reviewed six operating in the city and ranked them by specialisation, published Clutch scores and the kind of client each is built for.
Reviewed by Davis Paipa, Founder, Shoptank. Agency data verified 2026-09-17.
| # | Agency | Best for | Location | Rating |
|---|---|---|---|---|
| 1 | Re:signal | Enterprise eCommerce SEO | London, United Kingdom | 4.9 (4) |
| 2 | Passion Digital | Search-led performance marketing | London, United Kingdom | 4.7 (33) |
| 3 | ROAST | Integrated performance media SEO | London, United Kingdom | 4.9 (17) |
| 4 | Go Up | SEO with digital PR | London, United Kingdom | 4.9 (7) |
| 5 | Found | Multi-channel search performance | London, United Kingdom | Not published |
| 6 | SALT.agency | International and technical SEO | London, United Kingdom, plus Leeds and Boston | Not published |
Re:signal
Re:signal is an organic search agency focused on eCommerce, describing its promise as accountable growth for eCommerce brands that turns customer search behaviour into forecastable revenue. Clutch records its service mix as 100 percent search engine optimization.
A 100 percent SEO service mix with a 4.9 out of 5 Clutch rating and an enterprise-heavy client base. Clutch notes 65 percent of its clients exceed 1 billion dollars in revenue, with named brands including Under Armour, ASICS and Ocado.
You run a large eCommerce brand on Shopify or Magento and want organic search measured against revenue rather than rankings.
- Clutch records a 100 percent SEO service mix, making it a true specialist
- Enterprise eCommerce client list including Under Armour, ASICS and Ocado
- States 89 search award wins across European and Global Search Awards
- Only 4 Clutch reviews despite the size of the client base
- Heavily eCommerce-focused, a weaker fit for B2B or SaaS businesses
Passion Digital
Passion Digital describes itself as a search-led performance marketing agency that helps ambitious brands show up wherever discovery happens. Clutch records an even split between SEO and PPC, with additional AI search, content, CRO and analytics services.
Clutch rates it 4.7 out of 5 across 33 verified reviews, one of the deeper review bases among London search specialists. It has won multiple UK Search Awards, UK Paid Media Awards and BIMA Awards between 2022 and 2024.
You want SEO and paid search bought together from one London team with a well-documented public review record.
- 33 verified Clutch reviews, a deeper sample than most London SEO boutiques
- Multiple UK Search Awards and UK Paid Media Awards from 2022 to 2024
- Named clients include Knight Frank, OneTrust and Mazda
- Half the practice is paid media, so it is not an SEO-only shop
- The 5,000 dollar minimum project size rules out very small budgets
ROAST
ROAST describes itself as an international integrated performance marketing agency driving return on ad spend and growth in the new era of discoverability. Its organic practice covers SEO, technical SEO, content, app store optimisation, GEO and digital PR.
Clutch rates it 4.9 out of 5 across 17 verified reviews with SEO at 35 percent of its service mix. The agency is B Corp certified with a score of 91.1 against an 80-point pass mark.
You want SEO planned together with paid media across multiple markets and you value a certified B Corp partner.
- B Corp certified at 91.1 points against an 80-point pass mark
- Named clients include Experian, Rightmove and AllSaints
- Offices in London, Cape Town and Brooklyn support multi-region delivery
- SEO is about a third of the service mix, so it is not an SEO-only specialist
- The 5,000 dollar minimum project size rules out very small budgets
Go Up
Go Up describes itself as a leading London search marketing and SEO agency, offering SEO strategy, technical SEO, link building, digital PR, UX and conversion work, and paid media. Clutch records its mix as 60 percent SEO and 30 percent public relations.
Clutch rates it 4.9 out of 5 across 7 verified reviews with a low 1,000 dollar minimum. Its published client list spans consumer and B2B brands including Rapha, Hackett London and AnyVan.
You want SEO tightly coupled with digital PR and reputation work at a lower entry point than enterprise consultancies.
- SEO plus PR make up 90 percent of its Clutch service mix, a genuinely search-led agency
- The 1,000 dollar minimum project size is accessible for smaller brands
- London and Los Angeles offices support UK and US campaigns
- Only 7 Clutch reviews, a limited public sample
- Small team: Clutch lists 10 to 49 employees
Found
Found is a London digital marketing agency that describes itself as an AI-first agency built for digital marketing performance across every searchable platform. It began in 2005 as a PPC specialist, rebranded to Found in 2010, and now runs SEO, PPC, paid social, digital PR, data science and creative from London and New York.
Its about page records 90 or more marketing experts, 100 or more awards and nominations, Google Premier Partner status and five consecutive years in the Top 10 Great Places to Work, with named clients including Toolstation and PUMA.
You want SEO run inside a full multi-channel performance programme with paid media and analytics under the same roof.
- 90 or more specialists and 100 or more awards and nominations per its own about page
- Google Premier Partner status
- Offices in both London and New York support transatlantic campaigns
- No published Clutch, GoodFirms or G2 rating found, so third-party review evidence is limited
- Full-service breadth means SEO competes with other channels for internal focus
SALT.agency
SALT.agency describes itself as a specialist enterprise SEO agency and AI visibility consultancy working with global brands on organic search and AI visibility. Its services centre on technical SEO, international SEO, site migrations and AI search optimisation.
Established in 2014, it is one of the few UK agencies positioned purely around technical and international SEO rather than full-service marketing. Clutch records SEO as 80 percent of its service mix.
You have a large multi-language or multi-region site and need migration-grade technical SEO rather than content volume.
- Narrow specialisation in technical, international and migration SEO
- Offices in London, Leeds and Boston support combined UK and US programmes
- Clutch lists SEO as 80 percent of its service mix, confirming it is not a generalist agency
- Its Clutch profile is unclaimed and carries no client reviews, so third-party validation is weak
- Small team: Clutch lists 10 to 49 employees
How we ranked these agencies
- Depth of SEO experience, not general marketing
- Third-party review score on Clutch, GoodFirms or G2 where published
- Named services and a clear, public description of the offer
- Company longevity and team size
- Fit for enterprise versus small and mid-size brands
- Pricing transparency
- Evidence of real, named client work
Every agency listed is real and operating. Founding years, ratings and services come from the agency website or a third-party review platform, verified 2026-09-17. Where a figure is not published, the page says so rather than estimating.
Why work with a SEO agency in London
London agencies often run SEO alongside paid media and digital PR, which suits brands that want one team across channels. The trade-off is that SEO is rarely the whole practice.
The city also hosts genuine technical specialists working on international and migration-grade SEO. If you run a multi-language site, that depth is hard to find elsewhere in Europe.
Published minimums in this list range from 1,000 dollars to 5,000 dollars per project. Several London agencies do not publish pricing at all, which is noted on each card.
Frequently asked
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