Subdomain SEO is the practice of optimizing a subset of your website that appears before the primary domain name.
A subdomain differs from a subdirectory in structure, and search engines view both domains and subdomains differently.
While a subdirectory (domain.com/subdirectory) is considered part of the main domain, a subdomain (subdomain.domain.com) is viewed as a separate website.
Hence, subdomains are crawled and tracked separately, with their own DNS records and ranking performance. As a result, your primary domain site gets less benefit from subdomain links since SEO authority does not flow as freely between the two.
You should use subdomains when you want to organize distinct sections of your website where there is no need for the user to visit your main website. Incorrect usage of subdomains can lead to a massive loss in organic search visibility.
Let’s understand what SEO for subdomain is and when you should use it to boost your SEO rankings and traffic.
What is a Subdomain?
A subdomain is an addition to your primary domain, created using a prefix before the larger domain name. It helps to organize a distinct section of your website under a unique web address and content while remaining connected to the core brand.
Here is an example of a subdomain where the blog is the subdomain of our primary domain seoptimer.com:
For instance, Apple uses several subdomains to structure its website based on specific user needs.
- support.apple.com is dedicated to customer support resources
- tv.apple.com offers access to Apple TV’s streaming content
- developer.apple.com provides SDKs, APIs, and technical documentation
Each of these serves a separate purpose with different audiences, showing how their user journeys are distinct from the main homepage.
You should create a subdomain when you don't specifically want the visitors of the subdomain to visit your main website, allowing you to isolate experiences or functions.
You can do this by setting up a DNS record to route traffic to the right server or application.
Is a Subdomain Good for SEO?
There is no straightforward answer, as it depends on a case-by-case basis.
While there are potential SEO benefits for using subdomains in specific scenarios, improper use can limit the authority-building impact on your primary domain.
In short, subdomains are good for SEO only when:
- You need to create unique brand experiences for different audiences or services.
- Your content targets entirely different topical niches from the main website.
- You want to separate international sites (e.g., us.domain.com, fr.domain.com) for regional SEO strategies.
- A project requires independent hosting environments, CMS platforms, or teams.
- You are building a microsite or campaign hub that shouldn't affect the primary domain's structure.
- You need to keep certain sections (e.g., support, developer docs) isolated for technical or organizational reasons.
Can Subdomains Rank on Google?
Yes, subdomains can rank on Google, but they function as separate properties from the main domain.
Even Google's very own developers.google.com subdomain ranks for several keywords.
Google can index and rank your subdomains if you follow SEO best practices.
However, you should individually verify every subdomain on Google Search Console.
When you have several domains, it’s like maintaining a cluster of sites. Hence, it weakens the primary domain strength and link equity since your SEO efforts are distributed among several smaller websites.
Unlike subdirectories, subdomains do not automatically benefit from the main domain's SEO momentum, which can slow your organic growth.
To make your subdomains rank well, you need to ensure that each subdomain targets different keywords, offers high content quality, and drives a smooth user experience.
When you choose subdomains for the right reasons and optimize them with the same diligence as any other part of your site, they can perform just as powerfully as subfolders, dispelling the notion that Google "penalizes" them.
- Nikolay Krastev, Head of SEO at Growth Leads LTD
SEO Tactics for Subdomains
Here are the top SEO strategies to rank subdomains:
Ensure Proper Internal Linking
Linking important pages between your root domain and subdomain ensures link equity flows properly. Descriptive anchors should always be used so both users and crawlers can anticipate what they will find.
Subdomains don’t inherit authority from your main domain, which trips people up. But they do carry brand recognition, and in my experience, smart internal linking across your ecosystem can really help.
- Dominik Fajferek, Head of SEO at SEM House
Avoid assigning the same anchor text to different pages, especially within the subdomain. It confuses search engines and weakens the context of those links.
Aaron Whittaker, VP of Demand Generation & Marketing at Thrive Internet Marketing Agency, shared a great tip for creating anchor texts from your root domain to subdomains:
Optimize anchor text from your main domain’s internal links to reflect real query intent—not just brand terms. For one of our HVAC clients, switching from branded navigation links to descriptive anchors like “AC Troubleshooting Guide” increased subdomain traffic around over six weeks.
Each page on your subdomain should have at least one relevant internal link pointing to it. You should conduct an internal link audit to find disconnected or low-priority pages.
Pages that are difficult to reach from the homepage or primary navigation may not get indexed at all. Therefore, place important links higher up on the page to give them more weight.
Submit Subdomain Separately in Google Search Console
Subdomains must be submitted independently in Google Search Console because search engines treat them as separate properties.
Verification allows you to access dedicated performance data, such as impressions and click-through rates.
Each subdomain property in the Search Console also makes it easier to identify and fix technical SEO issues on the subdomain without affecting the root domain.
Proper submission ensures your subdomain gets crawled and indexed efficiently. It also lets you use tools like page experience reports to optimize your subdomain for more clicks and conversions.
Also, keyword data is more accurate when properties are tracked separately. You can track which keywords bring in more traffic and which pages on your subdomain receive the highest impressions so that you can further optimize them for user actions.
Use Canonical Tags Appropriately
Canonical tags help prevent duplicate content issues between a root domain and its subdomain.
When similar or identical content appears in both locations, a canonical tag tells search engines the preferred version to index. Without a proper canonical setup, search engines may split link equity or ignore important pages.
You should ensure canonical tags are correctly placed in the head section of your pages.
They should point to the version that holds the most value or serves as the primary source.
Avoid cross-canonicalization errors, which can create confusion for crawlers.
For blog archives or syndicated content, the canonical URL should be the original article. Proper use of canonical tags improves indexation and ranking consistency for domains and subdomains.
Build Backlinks to Both the Main and Subdomain
Both your root domain and subdomain need high-authority incoming links to rank on search engines.
Many site owners acquire inbound links only on the main domain and neglect the subdomain, which can limit the subdomain’s organic search visibility.
Note: You can use SEOptimer's Free Backlink Checker tool to view the link profile of your main domain and any subdomains. Our tool will show you detailed metrics like:
- Domain Strength
- Page Strength
- Total backlinks
- Total referring domains
- Top pages by backlinks
- And much more
You should treat each subdomain as an independent SEO asset that deserves its own backlink profile. Relevant backlinks to your subdomain help search engines rank your content. High-quality links also improve crawl frequency and ranking potential.
Avoid using the same link sources repeatedly for both domains.
Diversify your backlink acquisition efforts across blogs, directories, forums, and guest posts. And ensure anchor texts are long-tail, relevant, and match with each page's topic.
Contextual links placed within quality content have more value than those in sidebars or footers. A balanced backlink strategy benefits the overall domain authority and supports both parts of your site equally.
Maintain Consistent Branding and UX
Users hate annoying navigation and expect a smooth experience when switching between your root domain and subdomain.
Consistent branding builds familiarity and trust, especially when elements like logos, fonts, and navigation are in proper sync. If your subdomain looks disconnected from the main site, visitors may feel lost or question its authenticity.
When it comes to subdomains and SEO the biggest mistake I see is treating them like they’re disconnected from the main brand. Just because something sits on a subdomain doesn’t mean you can forget about cohesion. If Google’s crawling it, it should feel like part of the same experience, both technically and contextually.
- Lonnie Jones, Founder of Local SEO Help
A unified user experience reduces friction and supports longer session durations.
Follow the same design for the main site and subdomains to create continuity. Consistency in messaging and tone reinforces brand identity across all pages.
Both desktop and mobile experiences must feel intuitive and connected. A smooth transition between the subdomain and the main site strengthens credibility and boosts engagement metrics.
Should You Use a Subdomain for Your Blog?
No, you should not host your blog on a subdomain. A subdomain is treated as a separate site by search engines, which means any authority your blog earns may not fully benefit your primary domain.
Hosting your blog on a separate DNS won't transfer the subdomain's (blog's) link equity to the main site, resulting in lost SEO value.
Instead, you should use subdirectories (e.g., seoptimer.com/blog) for your blog.
Subdirectories are good for SEO as links acquired to the blog pass to the host domain, helping improve Domain Strength and organic rankings. If your blog ranks well and earns backlinks, keeping it within a subdirectory structure ensures that your main website shares those benefits.
Otherwise, there’s a risk of potential SEO fallout, with a weaker impact on rankings and diluted visibility across your brand.
Why Use a Subdomain on Your Website?
Here are the different reasons for using a subdomain on your website:
Segment Distinct Content Types or Functions
You should use a subdomain when you need to separate content that serves a different role from your main site. If each section requires its own structure, design, or functionality, you should place it on a subdomain.
Using a separate DNS for your subdomain helps you create a cleaner structure that allows each section to operate independently without affecting the core domain.
A great example of this is HubSpot Academy, which is hosted at academy.hubspot.com.
While HubSpot’s core business revolves around CRM, marketing automation, and sales software, the Academy operates as a value-added resource.
It offers free courses, certifications, and bootcamps designed to help marketers, sales professionals, and business owners grow their skills and careers.
By hosting this educational platform on a subdomain, HubSpot can use different layouts, navigation, and functionality tailored to online learning without interfering with the product-focused experience of its main site. It also allows the Academy to grow and scale as its own learning ecosystem while still benefiting from the authority and trust of the main hubspot.com domain.
Maintain Flexibility Across Internal Teams
Create a subdomain when you need to maintain flexibility across internal teams.
You should give departments with different responsibilities, such as training, partnerships, or internal operations, full control over their own areas of the website.
For example, a team managing partner resources can use partners.company.com to publish content, tools, and documents without depending on the central site. When you do this, each team works more efficiently, avoids delays, and updates their section without interfering with other teams.
Host Experimental or Staging Environments Safely
You should go for a subdomain when you need a separate space to test new features, designs, or entire versions of your site without touching the live version.
It allows your developers to run quality checks, experiment with layout changes, or test new tools while keeping the main website stable and unaffected.
Avoid SEO Risks from User-Generated Content
You should use a subdomain when you want to avoid Google penalties from UGC text.
For example, placing a public discussion forum on community.domain.com helps contain low-quality posts, duplicate content, or potential spam away from the primary domain.
Keeping such content isolated protects your main site’s authority, preserves content quality, and limits the chance of algorithmic penalties.
Drawbacks of Using a Subdomain for SEO
Here are the different disadvantages of using a subdomain for SEO:
Link Equity Does Not Transfer Effectively
You should avoid using a subdomain when your goal is to pass SEO value from blog posts, landing pages, or other content to your main site.
Any backlinks pointing to the subdomain do not directly strengthen the authority of the root domain. As a result, you miss out on the link equity that could have contributed to your primary site’s search rankings.
Harder to Rank Collectively
Avoid a subdomain when you want to rank a group of related content under the same topical authority.
Because subdomains operate separately in the eyes of search engines, they don’t contribute to the collective ranking power of the main site. This makes it more difficult to dominate search results across a topic cluster or related set of keywords.
Duplicate Content Risks Increase
You should be cautious when using subdomains if you have overlapping or similar content on both the main domain and the subdomain.
You may unintentionally create duplication, which can confuse search engines and lead to lower rankings or content being ignored.
Managing these risks becomes harder as your website grows.
Requires Separate SEO Efforts
Try not to use subdomains if you want to keep your SEO strategy efficient.
Subdomains require their own keyword research, backlink building, technical audits, and analytics setup. When you split your efforts between multiple domains, your workload increases without necessarily improving your results.
And the harsh reality is that if you don't have the resources to allocate to an entirely new site (the subdomain), then you shouldn't even bother setting it up.
Here’s the tough part: if you don’t have the resources to treat a subdomain like a proper project, just don’t do it. Too many end up as abandoned, half-baked corners of the web.
- Dominik Fajferek, Head of SEO at SEM House
Internal Linking Becomes Less Effective
Reconsider using subdomains when you rely heavily on internal linking for SEO.
Links between a subdomain and the main domain do not carry the same strength as internal links within a single domain. This reduces the ability to pass authority between pages and weakens the structural benefits of your internal link strategy.
Conclusion
You should be careful when using subdomains, as each one must be optimized individually with strong content, clean architecture, and backlinks.
Authority does not carry over automatically, so relying on your main domain alone won’t improve the rankings of subdomains. You should monitor indexing and performance separately to avoid SEO gaps.
Always prioritize a structure that supports your long-term goals. Use subdomains when your content needs separation and serves different audiences.
If your priority is faster SEO growth and unified authority, keeping everything under one domain is the better route.
