Office 365 with 2 domains

New Contributor


I have the following scenario:

Company 1, mail, 9 people.

Company 2, mail, 8 out of the previous 9 people.

I would like to have both addresses in Outlook, being able to receive and send from different addresses.

Do I have to purchase two licences per user, to manage 2 different addresses on different domains?

Do you suggest to add both domains to the same Administrator panel, or keep them separate?

Thank you very much,



2 Replies
best response confirmed by Fabio Nogarotto (New Contributor)

You can have multiple domains in the same tenant, and it's the preferred configuration for any scenario involving collaboration between people in said domains.


As for sending/receiving messages, things are trickier because Exchange Online only allows you to send by the primary SMTP address by default. You can have multiple addresses, associated with any number of domains, and receive messages just fine in the same mailbox. When it comes to sending though, you will have to use one of the available workarounds or third-party tools. This is a topic that is often discussed, so do a search online to find detailed descriptions of said workarounds/tools.

Hi @Fabio Nogarotto,


have a look at ChooseFrom for Exchange Online/Office 365 cloud service.