Allow external domains to access SharePoint (non 365 tenants

Question

Allow external domains to access SharePoint (non 365 tenants

Mark Lewis 0

I've setup a SharePoint site for a charity. They now want to allow access to various external organisations, some use 365, some Google and just basic email hosting. All the external organisations do have their own domain names for emails

Is there a way I can setup federated access or some other type of access to these external users?

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Answer 1

Hi @Mark Lewis,

Based on your inquiry, this can be done in SharePoint Online, but it is generally handled through external sharing and guest access rather than a separate federated access setup for the SharePoint site itself.

Technically, SharePoint supports sharing with external users at both the organization level and the site level, and the site can be configured more restrictively than the tenant if needed.

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For your scenario, the usual approach is:

Enable external sharing for the tenant and for the specific site if it is currently restricted.

A commonly used option for controlled collaboration is to allow sharing with new and existing guests, so external users authenticate instead of relying on open anonymous access.
You can find the detail information and the instructions in the article: Manage sharing settings for SharePoint and OneDrive in Microsoft 365 - SharePoint in Microsoft 365 …

Invite the external users as guests to the SharePoint site or share only the specific files/folders they need. This is the supported way to collaborate securely with partner organizations in Microsoft 365.
If you want to limit access to known partner organizations only, you can configure a domain allow list (or block list) at the tenant or site level.

For the different external organizations you mentioned:

If they already use a work or school account, they can be invited and authenticate that way.
If they do not use Microsoft 365, SharePoint can still support external access in supported sharing scenarios by sending a one-time passcode to the email address you shared with.

Additionally, a good best practice here is to use a separate partner or extranet site for external collaboration rather than opening a broader internal site. That makes permissions easier to manage and helps reduce accidental oversharing.

I hope this help. Please feel free to reach out if you have any further questions.

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Mark Lewis 0 Reputation points

2026-06-23T14:38:23.58+00:00

Hi,

Thanks for this, unless I'm reading it wrong, I don't think it will work for me

What would be nice is that I don't have to add anyone as a guest, if they try and view the site they are challanged requesting their email address, if that domain exist in the allowed domain list they are sent a OTP.

Thanks

Mark
Ian-Ng 14,150 Reputation points Microsoft External Staff Moderator

2026-06-23T21:14:21.19+00:00

Hi @Mark Lewis,

Thanks for clarifying.

However, SharePoint Online does not currently work that way for site-level access. The OTP experience is mainly used when content is shared with a specific external recipient, such as a file or folder shared by email. It is not a general domain-based self-entry mechanism for a whole SharePoint site.

A domain allow list can restrict which external domains users are allowed to share with, but it does not automatically grant site access to anyone from those domains. For SharePoint site access, external users normally still need to be explicitly granted access, usually through the guest access flow.

The closest supported approach would be to use a dedicated external collaboration site and manage access through invited guest users or approved groups. If you need fully open access, that will require a different sharing model, such as anonymous links, but that would not provide the same domain-based authenticated control.

I hope you understand the situation and appreciate for raising your inquiry again.