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Written By Harshita Sachdeva
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Approved By
Shivam Rathore -
Updated on September 16th, 2026
Migrate SharePoint Online Sub-Sites and Their Structure: Expert Guide to Move Sites, Lists, & Libraries
User Query: So actually we are migrating from SharePoint 2016 to SharePoint Online very soon. Consider this current structure, which includes hundreds of sites and nested subsites (e.g., /MyDepart/IT/Employees). Given the volume of sites we have, which approach is realistically feasible?. How do businesses now typically manage their environments in SharePoint Online? What’s the best tool, and how to utilize that tool before and during the migration?
– By Shirpars (IT Employee, Germany)
Introduction: SharePoint Online is a cloud-based platform built by Microsoft. That’s used to store, organize, and share files in a safe place. But sometimes, when we migrate SharePoint Online sub-sites and their structure, the migration becomes lengthy. This happens due to the large amount of data and complex structures. That increases the chances of leaving information behind. To overcome this problem, the Aryson Tenant-to-Tenant Migration provides you with many features. This makes the process of migrating data easier. Whether you need to move one subsite to another site in SharePoint or restructure an entire subsite.
What a Subsite Actually Is?
A subsite is a child site living inside a parent site or site collection. For example,
/xyzcompany/department/technical sits under /xyzcompany/department.
Theoretically, it seems very convenient and a proper approach to organize departments and projects properly under one roof. By default, it inherits permissions, navigation, and often the branding of its parent. Unless it breaks that inheritance to lock down a specific area. That inheritance is exactly what makes it painful to transfer a SharePoint subsite to another SharePoint parent site without breaking.
Permissions, navigation, content types, and even the URL itself are all defined relative to the parent site. Pull a subsite out of that relationship, and half of what made it functional stops working.
The URL changes and permission inheritance either break or have to be rebuilt. Navigation links that pointed to /sites/corporate/hr/policies now point to nothing. It’s common when you detach something that shouldn’t be detached. This makes it difficult to migrate SharePoint Online sub-sites and their structure.
How SharePoint Subsite Migration Actually Works
Ever tried looking for the “Move One Subsite to Another Site in SharePoint” button in SharePoint to relocate a subsite?. No, as it doesn’t exist because Microsoft never developed that function, and they no longer recommend using direct subsites. That’s the serious problem with SharePoint Online, which makes it impossible to do structural migration. That leaves a lot of IT admins stuck with a huge problem. Maybe you are part of an organization that built its platform on a subsite hierarchy many years back. For example, consider a subsite hierarchy like this:
HR under Corporate, Finance under Corporate, and “Team A > Project X > 2023 > Archive.” Now that content needs to live somewhere else, either because of a tenant merger or because your organization decided to follow a flat architecture to prevent it from collapsing. It’s hard to migrate SharePoint Online sub-sites and their structure cleanly anywhere in the Microsoft 365 stack.
This blog covers how to migrate SharePoint Online subsites. What are the differences between native options and a dedicated migration tool?
Why Did the Structure Become Problematic Later?
SharePoint subsite migration, especially into a different site collection, is a different problem for a few specific reasons.
- There’s no native function to migrate SharePoint Online subsites.
- The site manager lets you rearrange subsites, but only inside the same site collection.
- There’s no direct way to transfer SharePoint subsite to another SharePoint parent site.
- Permission inheritance doesn’t get transferred cleanly.
- Unique permissions set at the subsite or item level generally need to be recreated.
- URLs and navigation break by default.
Why a Dedicated Migration Tool Is Needed
Native SharePoint doesn’t have any way for a subsite to be migrated to a different site collection. Organizations go through problems such as permission breaks or invalid URLs. Every time, the site structure had to be rebuilt. All this is doable for a single website, not for a lot of sites.
This is the exact gap a purpose-built tool like the Aryson Tenant-to-Tenant Migration Tool, which lets you move subsite to another site collection (SharePoint Online) cleanly, exists to close:
- Moving document libraries.
- Generic lists, document sets.
- Folders from one SharePoint site into another site or site collection directly.
All of this can be done without any guidance. So, for the migration of SharePoint, two methods are
- Manual Method Using Microsoft SPMT
- Aryson Tenant-to-Tenant Migration Tool
Method 1: Manual Method Using Microsoft SPMT
In manual steps, there are several other ways. The recommended method is to use Microsoft’s SharePoint Migration Tool (SPMT).
- Install and configure the SPMT tool.
- Connect it to your current SharePoint 2016 environment.
- Select the required libraries.
- Configure your new SharePoint Online.
- Match your current libraries/list with the new ones.
- Now, to migrate SharePoint Online subsites, start the migration.
- After migration, check migration reports for any errors.
- Validate the Migration Files.
Drawbacks of Manual Methods
The methods above are not wrong. But for SharePoint Online site structure, they are slow. That leads to an increase in workload over time; some of their limitations are
- It doesn’t scale; moving one subsite manually is lengthy.
- Permissions should be manually checked. One wrong permission can lead to losing access over the subsite.
- Navigation and links should be fixed whenever the URLs change or a subsite is migrated.
- No GUI, and if something goes wrong, it can be checked only by logs or once websites go live.
Method 2: Aryson Tenant-to-Tenant Migration Tool
The manual methods became challenging for larger SharePoint subsites, and chances of inconsistency increased. Therefore, it’s recommended to use the Aryson Tenant-to-Tenant Migration. It’s built with the purpose of helping admins migrate SharePoint Online sub-sites and their structure. To reduce their dependence on native tools that don’t support cross-migration.
Key Features of the Aryson Tenant-to-Tenant Migration Tool
- Direct site-to-site collection migration—moves document libraries, generic lists, document sets, and folders straight into a new SharePoint site or site collection.
- Batch migration—multiple SharePoint sites can be queued and migrated together instead of one at a time, which is important.
- Date Filter – Get only those pieces of content that are modified within a chosen date range.
- List and Library filters—content type, file extension filters, custom older path, and file size filter can be modified.
- Real-time GUI—tracks the migration in real time, with options to stop a process mid-run.
- Detailed and summary reporting—provides a record of exactly what moved.
- 24/7 support—It provides support to its users to solve their queries.
How to Use Aryson Tenant-to-Tenant Migration
| Steps | Description |
| Downloading and Installation | Download and open the Aryson Tenant-to-Tenant Migration Tool with admin rights. |
| Sign in to your account. | Sign in to your Microsoft account through the authentication window. |
| Setup | Choose SharePoint Card, then select the “SharePoint to SharePoint” box. |
| Choose authentication type. | Select Modern Authentication and authenticate it. (Choose Admin Access for larger migration.) |
| Connect Source and Destination Tenants | Connect the source tenant and source sites with valid credentials. Do the same for the destination. |
| Mapping Sites | Map the source and destination sites and preview the mapping before migration |
| Apply Filters | Apply the List/Library options, Date Filter, or File Filter according to your needs. |
| Track Progress | Monitor progress through the dashboard |
| Migration and Review | Start the transfer. Once complete, verify it to check if anything is missing. |
Note: For a proper and detailed process to migrate SharePoint Online sub-sites and their structure, it’s recommended to check the Software Guide.
Conclusion
If you want to transfer SharePoint subsite to another SharePoint parent site that has a smaller number of subsites. The manual route is perfectly workable. But for hundreds of sites, and to completely migrate SharePoint 2016, that is not possible manually. Hence, for these types of cases, the Aryson Tenant-to-Tenant Migration Tool is the right choice. Which can handle the bulk transfer with a maintained structure. So most people follow the structural decisions and prefer a conversion tool.
Frequently Asked Questions
Q1) Will the Aryson Tenant to Tenant Migration Tool preserve my folder hierarchy during SharePoint migration?
Ans. Yes, the Aryson Tenant to Tenant Migration Tool keeps the original SharePoint site’s hierarchy safe during the migration process. Therefore, your libraries and folders can be migrated easily. Which helps users see their content in the new environment without any change in folder structure.
Q2) Will my permissions be saved after the migration?
Ans. Yes, the tool preserves access permissions during migration. It ensures that the SharePoint migration can migrate permissions along with the SharePoint data. But sometimes the permission preservation depends on the source and destination environments. Because permissions migration requires appropriate user mapping, and inherited and unique permissions can behave differently during migration.
Q3) Can I migrate multiple sites at once using the Aryson Tenant to Tenant Migration Tool instead of moving them individually?
Ans. It supports migration of multiple SharePoint sites, which makes it possible to manage larger migration projects. Admins can see the available SharePoint sites and select the particular sites they want to migrate.
Q4) What happens to old links and bookmarks pointing to the subsite after migration?
Ans. Some old links and bookmarks don’t work automatically after a migration. A migration can change the site’s URL, tenant address, etc. So bookmarks that point to the old location may require an update unless a URL-preservation type mechanism has been set.
Q5) How long does migrating a subsite’s structure usually take?
Ans. There is no fixed time because the duration depends on the size and complexity of the subsite. A smaller subsite containing a limited number of folders may migrate faster than a large site containing more files, etc.
Q6) Does this software support SAN and NAS storage systems?
Ans. Yes, the Aryson Tenant-to-Tenant Migration Tool works perfectly fine on these types of storage systems if it’s in a proper structure.
Q7) Is it possible to transfer a SharePoint subsite to another SharePoint parent site?
Ans. Yes, it’s possible for sites that are in the same file collection. For them, SharePoint provides the option to migrate subsites that are within the existing hierarchy of sites. In the case of different destinations for the old and new site collections, a different migration approach is recommended.
Q8) How can I migrate data between SharePoint sites?
Ans. With the help of the Aryson Tenant-to-Tenant Migration Tool, the process becomes much easier, which lets you
⏩Select the current SharePoint site.
⏩Choose the destination of the new SharePoint site.
⏩Then match the current and future destinations.
⏩Start the migration.
About The Author:
Harshita Sachdeva, a professional technical writer at Aryson Technologies, specialize in delivering clear, hands-on documentation for data management, migration, and recovery solutions. With a meticulous, reader-first approach, I break down complex technical processes into simple, actionable content - helping IT professionals and decision-makers tackle challenges efficiently.
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