If you've ever searched for your own business on Google and found your competitors sitting above you, you've probably wondered whether an SEO agency could help. But what is an SEO agency, and what do they actually do all month?
In this guide I'll explain exactly what an SEO agency does, how it differs from a freelancer or consultant, and how to tell whether your business needs one. I run SERPentity's SEO services, so I'll show you what happens behind the scenes.
What Is an SEO Agency?
An SEO agency is a company that helps businesses rank higher in search engines like Google, so more of the right people find them. SEO stands for search engine optimisation.
You'll also see the terms SEO company and SEO firm. They all mean the same thing: a team that improves your website's visibility in organic (unpaid) search results.
The goal isn't just rankings, though. A good SEO agency focuses on what rankings bring in: website visitors, phone calls, enquiries and sales.
In simple terms: an SEO agency makes your website easier for Google to understand, more useful for your customers, and more trusted than your competitors' sites.
What Does an SEO Agency Actually Do?
This is where a lot of business owners get frustrated. They pay an agency every month but have no idea what's being done. Here's what the work should actually involve.
1. Audit and strategy
Every good campaign starts with an SEO audit. We look at your website's technical health, your content, your backlinks and your competitors. That shows us what's holding you back and where the quickest wins are.
From there, we build a strategy covering which keywords to target, which pages to create or improve, and what order to tackle it all in.
2. Technical SEO
Technical SEO makes sure Google can find, crawl and understand your website. It covers site speed, mobile-friendliness, site structure, broken links, duplicate content, schema markup and indexing issues. If these foundations are weak, nothing else works as well as it should.
3. On-page SEO and content
This is about making each page as relevant and useful as possible for the searches you want to appear in. It includes writing and improving service pages, optimising page titles and headings, creating location pages and publishing helpful articles that answer your customers' questions.
4. Off-page SEO and link building
Google trusts websites that other reputable websites link to. Agencies earn these links through digital PR, local partnerships, directories, industry sites and genuinely useful content. Read more in our guide to link building.
5. Local SEO
For businesses serving a specific area, agencies optimise your Google Business Profile, build local citations, help generate reviews and create location-specific content. This is how you appear in the Google map pack. See our local SEO services.
6. Reporting
You should receive clear, regular reports showing what's been done, how rankings and traffic have changed, and, most importantly, how many enquiries or sales came from organic search.
SEO Agency vs Consultant vs Freelancer vs In-House
There's more than one way to get SEO done. Here's how the options compare.
| Option | Pros | Cons |
|---|---|---|
| SEO agency | Broad skills (technical, content, links), scalable, accountable | Costs more than a freelancer |
| SEO consultant | Deep expertise, strategic advice | Often advises rather than does the work |
| Freelancer | Lower cost, flexible | Limited capacity, may lack some skills |
| In-house hire | Knows your business inside out | Salary, training, tools and holiday cover |
An SEO consultant usually advises on strategy and leaves your team to implement it. An agency typically does both: it plans the work and carries it out.
For most small and medium businesses, a small, specialist agency offers the best balance. You get a range of skills without the cost of a full-time hire, plus a direct relationship with the people doing the work.
Why Hire an SEO Agency?
Time. SEO takes consistent effort every month. Most business owners simply don't have the hours.
Expertise. Google's algorithm changes constantly. Agencies keep up with those changes so you don't have to.
Tools. Professional SEO tools for keyword research, rank tracking and site crawling cost hundreds of pounds a month. An agency already has them.
Results that compound. Unlike ads, which stop the moment you stop paying, good SEO keeps generating traffic long after the work is done.
Signs Your Business Needs an SEO Agency
- Your competitors appear above you on Google for your main services
- Your website gets little traffic or very few enquiries
- You rely heavily on paid ads, referrals or directories for leads
- You've launched a new website and traffic has dropped
- You don't appear in the local map results for your area
- You've tried DIY SEO but don't have time to keep it going
If two or more of those sound familiar, it's worth at least getting a professional opinion.
What Working With SERPentity Looks Like
At SERPentity, we keep things simple and transparent. We start with a free audit so you can see exactly where your website stands. Then we agree a plan built around your goals and budget, and do the work: technical fixes, content, local SEO and link building.
You'll deal directly with me and my team rather than being passed between account managers. We report in plain English, focusing on the numbers that matter to your business.
Our clients range from care providers in Sheffield and Leeds to ecommerce artists and UK-wide manufacturers. Take a look at our case studies to see the results.
What an SEO Agency Won't Do
It's just as useful to know what an SEO agency can't do, so your expectations are realistic from day one.
It can't guarantee rankings. Google controls its results, and no agency can promise a specific position. Anyone who does is overselling.
It can't deliver lasting results overnight. Quick wins do happen, especially with technical fixes and local SEO, but sustainable rankings are built over months.
It can't fix a website that doesn't convert. SEO brings visitors to your site. If the site is slow, confusing or hard to use on a phone, those visitors won't turn into customers. That's why we often look at web design and SEO together.
It can't do it all without you. The best results come when you share knowledge about your customers, answer questions promptly and ask happy clients for reviews. SEO works best as a partnership.
How SEO Agencies Are Changing With AI Search
Search is changing. Google now shows AI-generated overviews for many queries, and more people use AI assistants to research products and services. A modern SEO agency should be helping you appear in these answers as well as the traditional blue links.
That means clear, well-structured content that directly answers customer questions, strong schema markup, consistent business information across the web, and a trusted reputation built through reviews and quality links. The fundamentals of good SEO haven't changed, but how they're applied is evolving quickly.
Quick Wins You Can Do Before Hiring an Agency
If you're not ready to hire an agency yet, a few simple steps will put you in a stronger position. Claim and fully complete your Google Business Profile. Ask your last ten happy customers for a Google review. Make sure every core service has its own page with a clear title. Connect Google Search Console so you can see how Google views your site. When you do bring in an agency, these foundations mean they can focus on the bigger opportunities straight away.
Final Thoughts
An SEO agency's job is simple to describe but takes real skill to deliver: get the right people to find your business on Google, then turn them into customers. The best agencies are transparent about what they do and measure success by your results.
If you want to know what an agency could do for your business, request a free SEO audit. Read our guide on how to choose an SEO agency too.
