The question is usually framed as in-house or agency. The answer at enterprise scale is almost always "both, in a sequence", and the interesting question is which comes first. This guide gives the costs, the failure modes and the sequence we see work.
The three models
In-house team. A director plus specialists, owning strategy and execution, working directly with engineering and content. Fully loaded cost $350,000 to $900,000+ a year in US markets, 6 to 12 months to hire, and it takes a further 6 months to become effective on a large site.
Agency programme. An external team running strategy and delivery inside your release process. $12,000 to $50,000+ a month for credible enterprise scope. Fast to start, hard to make accountable without a senior owner on your side. See enterprise SEO services for what a managed programme includes.
Consultant plus in-house execution. A senior consultant setting priorities, reviewing tickets and releases, reporting to executives, while your SEOs, content team and developers execute. $6,000 to $15,000 a month. The most cost-effective model when you have execution capacity, and useless when you do not. That is enterprise SEO consulting.
Full numbers in the enterprise SEO pricing guide.
Where each model fails
In-house fails when the director role is empty (it is, in most enterprises, for months at a time), when the team is junior and cannot defend priorities in sprint planning, and when the function is judged on rankings rather than shipped work. It also fails on peaks: a migration or a replatform needs more senior capacity than a steady-state team has.
Agencies fail when nobody on the client side owns the relationship, when recommendations arrive as audits rather than tickets, when senior people leave the account after the pitch, and when the agency's forecast is not tied to engineering capacity. Most of the enterprise SEO horror stories we hear are agency programmes that ran for two years without a client-side owner.
Consultants fail when there is nobody to execute. A consultant can write the perfect backlog and it will not ship.
The sequence most enterprises end up using
- Audit first. A fixed-scope enterprise technical SEO audit produces the ticketed backlog and tells you the real size of the problem. $15,000 to $40,000, four to six weeks. Do this before choosing a model.
- Agency or consultant to build the operating system. Ticket format, release checks, reporting data model, prioritisation cadence. If you have execution capacity, consulting. If you do not, a managed programme. 6 to 12 months.
- Hire the director into a working system. Recruiting into a function that already ships is faster and the candidate pool is better. The agency or consultant helps write the job description and interviews.
- Reduce the external scope. The agency becomes consulting, then a quarterly review. Any agency unwilling to work itself down is the wrong agency.
Start with an enterprise technical SEO audit before you lock a model. The sequence protects against the two common disasters: 12 months of nothing while the director role is open, and two years of agency fees with no internal owner.
Questions to decide it faster
- Who will attend sprint planning for SEO next month? If the answer is nobody, you need a consultant or agency now.
- Is there a migration in the next 12 months? If yes, you need senior external capacity regardless of the in-house plan.
- Does the board want an AI visibility number? If yes, someone has to own prompt-set measurement.
- Can the in-house team turn an audit into tickets with acceptance criteria today? If not, that is the first thing an external partner should build.
If the board wants an AI visibility number, see enterprise AEO and GEO services. Pressure-test the budget with the enterprise SEO ROI calculator.
