How to Merge Two Office 365 Accounts Using Outlook & Admin Tools

Published By Mohit Kumar Jha

Approved By Admin

Published On July 30th, 2025

Reading Time 8 Minutes Reading

Merging two Office 365 accounts isn’t officially supported by Microsoft, but I found a few effective ways to do it. I used Outlook, admin tools, and a professional solution to merge two Office 365 accounts effortlessly. 

Here, I will explain all these approaches step by step. So, without wasting time on the intro, let’s quickly start our discussion. 

Why Need to Combine Office 365 Accounts?

First, let me explain the common scenarios where merging accounts is necessary:

• Company mergers or acquisitions (Office 365 tenant to tenant migration)
• Consolidating personal and work accounts
• Cleaning up duplicate user accounts
• Centralising data for compliance or security reasons

Whatever the reason, if you have decided to consolidate Microsoft 365 accounts, this guide is for you.

Can I Merge Two Office 365 Accounts?

Not directly. Microsoft doesn’t provide any native tool or direct steps to combine Office 365 accounts. 

Here are the reasons why you can’t merge them directly:

1. Each Office 365 account has a separate tenant, with its own Azure AD, Exchange, SharePoint, and other services. Moving these isolated environments individually is not practical.
2. Microsoft hasn’t built a tool or API that allows combining two accounts into a single account automatically.
3. Licenses are specific to each account. You can’t transfer licenses or merge subscriptions between two separate personal/business accounts.
4. A custom domain can only be verified in one tenant at a time. You’d need to remove it from one tenant before using it in another.
5. Merging accounts could create security and identity.

While you can’t merge two Office 365 accounts natively, you can manually migrate or transfer data between them using:

• Microsoft Outlook (Export/Import PST)
• IMAP migration
• Office 365 account-to-account migration for businesses
• Automated Utility

Here are the precise details and steps of these solutions:

#Technique 1. Combine Office 365 Accounts Via MS Outlook Clients

Since there’s no built-in merge feature, you have to use Outlook clients. With them, you have to export data from your current Office 365 account, then import that to the new one.

The steps are divided according to the MS Outlook types:

Desktop-Based Outlook

1. Open Outlook Desktop, if not installed, download it first.  
2. Then, click on the File option > Add Account, and add a source Office 365 account.
3. Once the account sync prompt appears, again press the File option.
4. Afterwards, hit the Open & Export > Import/Export buttons.
5. Select Export to a file, then choose Outlook Data File (.pst).
6. Selected the mailbox folders to save them to a PST file.

Next, connect a target Office 365 account in the same Outlook:

1. Add the second account using File > Add Account.
2. Then, back to File > Open & Export > Import/Export and select Import from another program or file.
3. Lastly, browse and select the PST file.

New Outlook Client to Merge Two Office 365 Accounts

1. Within the Settings cog, select the Accounts option.
2. Now, hit the Your Accounts option, and Add Account.
3. Enter the second email address and select Microsoft 365 as the provider.
4. Enter the password and complete the login process.
5. Wait for the success message. Once it prompts, your account is synced.

Outlook Mobile App to Combine Office 365 Accounts

1. Click on the profile icon.
2. Hit the + icon and then Add an account.
3. I typed in my second email address and password, and it appeared within the app.

Note: The Outlook web version doesn’t allow for to use of more than one account at the same time. That’s why we can’t use it for merging Office 365 accounts.

This way, I merged my emails, contacts, and calendars into my new Office 365 account using different Outlook clients. No doubt it is free and easy to use, but this can be time-consuming with large data. 

#Technique 2. Merge Two Office 365 Accounts by Account-to-account Migration

Migrating data from one Office 365 account to another is a better option. But it requires some prerequisite steps also, which are as follows: 

• Global Admin access on both source and destination accounts
• Valid Office 365 licenses, user account creation, and mailboxes provisioned in the destination tenant
• Azure AD App registration in both tenants to combine Office 365 accounts smoothly
• Required API permissions granted:
  • Microsoft Graph: User.Read.All, Group.Read.All, Sites.Read.All, Mail.ReadWrite
  • Exchange: full_access_as_app
• Admin consent granted for the Azure app
• App credentials generated: Client ID, Tenant ID, Client Secret
• Mapping CSV file with source and target user

After confirming all these Office 365 migration checklist, follow these instructions to merge two Office 365 accounts:

1. In the source Exchange Admin Center, enable IMAP access by clicking on Settings. Then, under that, select  Mail flow > IMAP access, and turn it on.
2. Ensure Multi-Factor Authentication (MFA) is enabled for added security (optional).
3. In the target tenant, create new mailboxes for each user.
4. Assign Microsoft 365 licenses to each of these mailboxes.
5. Create a CSV file containing the usernames, email addresses, and credentials for the migration.
6. Again, open the target Exchange Admin Center, and hit the Recipients option, then Migration, select Add migration batch, and choose IMAP migration.
7. Now, upload the CSV file, enter the IMAP server details for the source tenant, and start the migration.
8. Once the transition is completed, update the DNS/MX records to direct mail flow to the new tenant.

This way, you can use your two different Office 365 accounts from one.

Quick Steps to Combine Office 365 Accounts

Now, follow the step-by-step instructions of this specified advanced utility to merge two Office 365 accounts:

• Step 1. On the first screen, you’ll see two Microsoft 365 options; click on both of them.
• Step 2. Now, select the data category, and leverage a Date Filter option if required.
• Step 3. To access the source account data, provide the Admin Email & Application ID, and validate them. Similarly, enter the credentials in the destination window. 
• Step 4. For processing source account users, use either the Fetch Users, Import Users, or Download Template options. 
• Step 5. Hit the Start Migration button.

Important Points

• You can’t move a license, only reassign it in the target tenant.
• Notify users of the switch and give them login instructions.
• Always ensure Office 365 backup using eDiscovery/export tools before migration.

Is It Safe to Merge Two Office 365 Accounts?

Yes, you just need to verify: 

• MFA enabled
• Auditing and logging active
• A rollback plan if anything fails

What If You Want to Merge Two Mailboxes in the Same Tenant?

If the accounts are within the same tenant, it’s easier:

• Export mailbox data from one user to a PST via eDiscovery or Outlook
• Import it into the other account’s mailbox
• Update aliases and permissions as needed

Author’s Verdict

While there’s no official “merge” button for Office 365 accounts, I’ve found three solutions that will help to merge two Office 365 accounts with minimum disruption. I’m sure, opting for any helps you to combine Office 365 accounts with expected results.