The Best Multilingual SEO Agencies, Vetted by a Practitioner

A multilingual SEO agency gets your pages ranking and cited in languages other than English. The work rests on one question, which is who writes the content in each language. A native writer living in the market knows how local buyers phrase a search. A translator working from English copy carries the English keywords across word for word.

I run international SEO programs in English, French, German, Italian and Spanish, and I built my first agency in Spain with roots in translation and localization. I checked every agency below on its own website in October 2026 for its languages, how it produces content in each one, named clients and pricing. This list focuses on language work. For agencies that also handle market entry strategy, see our international SEO agencies list.

How I vet a multilingual SEO agency

Ask who writes each language

Ask for the name and location of the writer for each target language. Then request a sample page and have someone on your local sales or support team score it for tone, terminology and accuracy. For an ecommerce marketing platform, translated versions of English pages sat in the mid-20s in France. Native writers rebuilt the market around local search habits, and the client tripled its top-3 rankings in France within six months.

Ask how they research keywords in each language

Keyword research translated from English misses the terms local buyers use. Ask the agency to show keyword research done natively in your target language, with local search volumes. Our guide to international keyword research shows what that looks like.

Ask how they decide what to localize

Some English pages localize well because the search intent matches across markets. Others need a full rewrite, and some topics have no local demand. A good agency audits your existing pages before translating anything. Our post on localization versus translation for SaaS covers how we make that call.

Test the hreflang setup with a rendered crawl

Google ignores hreflang tags unless each language version points to the other. Ask how the agency checks hreflang and rendering. During a content audit for an AI tax research platform, a JavaScript-rendered crawl showed 99.9% of the Canadian answer pages redirecting client-side to their US versions, even with hreflang tags in place. Our hreflang guide covers the markup.

Ask how they track AI answers in each language

In an analysis of more than 20 million ChatGPT fan-out queries, Peec AI found that 43% of background searches for non-English prompts ran on the English-language web (Peec AI, February 2026). Your English and local pages both shape what AI assistants say to a buyer in Madrid. Ask the agency to show prompts written natively in each language and run from each country.

The best multilingual SEO agencies compared

1. Flying Cat

Best for: B2B SaaS companies that want native content in French, German, Italian or Spanish with a senior strategist on every call.

Flying Cat is the founder-led boutique I run from Los Angeles. I lead strategy on every account. Native linguists who specialize in SEO research the local keywords and write or localize every page, and our French coverage includes Belgium, Switzerland and Canada. Each market starts with an audit of your existing English pages to decide which to localize, which to rewrite and which new pages to create.

• ActiveCampaign: 83,000+ more non-branded clicks and 4.1M+ more impressions across French, Italian, German and Spanish in eight months.
• Ecommerce marketing platform: top-3 rankings in France grew 3.2x within six months, and organic conversions in France rose 60% in year one.

Pricing: SEO translation from $0.50 a word with no retainer. Full international SEO programs from $5,000 a month.

2. GA Agency

Best for: Consumer, fashion and travel brands that want one in-house native team running SEO across many European markets.

GA Agency is based in London. It says its native specialists cover 26 markets and 18 languages, and it states that native specialists in-house do all the work instead of outsourcing or translation. Native speakers plan and run the work in their own market. Services include localized keyword research, hreflang, localized copywriting, international technical audits and link building through local directories and platforms in each market.

GA Agency reports a 170% revenue increase in one year across 15 countries for Calzedonia Group. It sells one strategy, one team and one fee across all markets.

Notable clients named on its site: Calzedonia Group, Expedia, Prada, Diesel, UniCredit, Pronovias.

3. Mintense

Best for: B2B and manufacturing companies entering the US, Italian, French or German markets that want native-written pages.

Mintense has offices in Verona, Lille, London and the US. It reports 200+ international SEO projects since 2008, with campaigns in 16 languages across 60+ countries. Its site states that every language version is written by a native-language team member, with machine translation kept for low-priority utility pages, if used at all.

Services include keyword research rebuilt per language, hreflang within a centrally managed technical setup, localization, audits and link building. Mintense works on a monthly subscription with no binding long-term contract.

Notable clients named on its site: Philips Evnia, ITW, Salvagnini, Numalliance, Piusi.

4. COSEOM

Best for: B2B SaaS companies expanding into European languages that want SEO plus AI search tracking per market.

COSEOM has offices in Barcelona, San Francisco and Bangkok, and its team works daily in Spanish, English and German. Native writers adapt copy for each market. Services include multilingual keyword research, per-market landing pages, technical SEO, migrations and local SEO. Its multilingual AI search visibility service measures ChatGPT, Gemini and AI Overviews in each market with a share-of-answer report.

Notable clients named on its site: Conga, TravelPerk, Torq, Onit, National Instruments, WinZip, Babbel.

5. Locaria

Best for: Enterprise and retail brands that need SEO tied to a large localization and transcreation operation.

Locaria is part of Stagwell and works in more than 50 languages across more than 90 markets. In-market specialists research keywords and write SEO content, backed by a network of 1,400+ linguists, translators and post-editors. Related services include transcreation and AI translation with human post-editing. SEO services cover international keyword research, multilingual content optimization, hreflang audits and GEO.

For Sally Beauty, Locaria reports a 400% increase in page-one rankings in Germany.

Notable clients named on its site: Sally Beauty, Autodesk, Hibob, Kate Spade, Easyhotel, Molekule.

6. Adapt Worldwide

Best for: Global enterprises that want performance marketing and international SEO backed by a large localization group.

Adapt Worldwide is part of Welo Global, and Welocalize's multilingual SEO page now points to Adapt. It describes 80+ in-market specialists who produce and adapt content per market instead of relying on automated translation. Services cover per-market keyword and intent research, localized content, international technical SEO including hreflang, AI SEO and app store optimization.

For a global technology brand across 7+ markets, Adapt reports impressions up 595% and key events up 113% in six months.

Notable clients named on its site: Uber, LinkedIn, Spotify, Booking, Panasonic, Kuehne + Nagel.

7. Oban International

Best for: Brands that need in-country review in many markets, including less common ones in Africa and Asia.

Oban International is based in Brighton and works through 450+ local in-market experts in 80+ countries. A second native-speaking expert checks every piece of work. Services include localized keyword research, international SEO strategy and domain strategy, technical audits, migrations, training and an AI search visibility audit. The expert network is paid for only when a market needs it.

Notable clients named on its site: BBC World Service, Burberry, Jo Malone London, Merlin Entertainments, AXA.

8. ICS-digital

Best for: Brands in finance, health or other regulated sectors that need content and digital PR in many languages.

ICS-digital is based in Leeds and says it covers 100+ languages and 58 countries with 300+ international writers and editors. Services include regional keyword research, localization, international link building through publisher partnerships and GEO for ChatGPT and Perplexity. A sister company handles translation.

For Patient Claim Line, it reports conversions up 394%. Its FAQ says focused campaigns start at a few thousand pounds a month.

Notable clients named on its site: IG, Deliveroo, bet365, Betfair, Skilling.

9. SEOProfy

Best for: Companies that want an execution team for keyword research, hreflang and link building in each country.

SEOProfy is based in Orlando and reports experience across 45 countries and 12+ languages, with native speakers handling localization. Services include local keyword research, content writing and localization, hreflang, regional sitemaps and link building through local sites in each country, plus a separate AI SEO service.

Notable clients named on its site: Jooble, FXTM, AutoDoc, Preply, Softros Systems, Lensa.

What multilingual SEO agencies cost

Few agencies on this list publish prices. Flying Cat's SEO translation starts at $0.50 a word, and international programs start at $5,000 a month. ICS-digital says focused campaigns start at a few thousand pounds a month. Mintense works on a monthly subscription without a long-term contract.

Content volume per language drives the cost more than anything else. ActiveCampaign's program produced about twenty new pages per language each month. When you compare quotes, ask how many pages per language each one includes, who writes them and who reviews them in the market.

FAQ

What is the difference between multilingual and international SEO?

Multilingual SEO makes your site rank in several languages, covering native content, local keywords and hreflang. International SEO adds market entry strategy, such as which countries to target first and how to structure your site for them. Our multilingual SEO guide covers the language side in detail.

Should I use machine translation for SEO?

Machine translation carries your English keywords into another language word for word, so the pages target phrases local buyers rarely type. It can work for low-priority utility pages. Pages that sell need native keyword research and a native writer.

How long does multilingual SEO take to show results?

Plan for three to six months before a new language shows steady movement. ActiveCampaign's results came over eight months. The ecommerce marketing platform tripled its top-3 rankings in France within six months.

If you are planning content in French, German, Italian or Spanish, book a call. I will review your current setup and show you where your first gains would come from.